1994 gmc sierra service repair manual by ujhsenfnse

FULL-SHE

1988-9£ r^PAIR MANUAL

Covers all U.S. and Canadian models of Chevrolet/GMC Pick-ups, Sierra, Blazer, Tahoe, Yukon and Suburban; 2 and 4 wheel drive gasoline and diesel engines

by Thomas A Mellon, A.S.E., SAE. Automotive Books PUBLISHED BY HAYNES NORTH AMERICA. Inc.

AimDMCTIVIr

ASSOCIATION

9876543210

Haynes Publishing Group Sparkford Nr Yeovil Somerset BA22 7JJ England

ABODE FGHI

Haynes North America, Inc 861 Lawrence Drive Newbury Park California 91320 USA 3N3

Chilton is a registered trademark of W.G. Nichols, Inc., and has been licensed to Haynes North America, Inc.

Contents GENERAL INFORMATION AND MAINTENANCE

ENGINE ELECTRICAL

ENGINE AND ENGINE OVERHAUL

DRIVEABILITY AND EMISSION CONTROLS

FUEL SYSTEM

1-2

HOW TO USE THIS BOOK

1-10

1-2

TOOLS AND EQUIPMENT

1-4

SERVICING YOUR VEHICLE SAFELY

1-35

FLUIDS AND LUBRICANTS

1-46

TRAILER TOWING

1 -5

FASTENERS, MEASUREMENTS AND CONVERSIONS

1-47

JUMP STARTING A DEAD BATTERY

1-48

JACKING

1-7

SERIAL NUMBER IDENTIFICATION

1 -50

MAINTENANCE INTERVALS

2-2

HIGH ENERGY IGNITION (HEI) SYSTEM

CHARGING SYSTEM

2-2

2-7 2-8

DISTRIBUTOR IGNITION (Dl) o Q SYSTEM

2-6

FIRING ORDERS

3-2

ENGINE MECHANICAL

3-56

EXHAUST SYSTEM

4-2

GASLINE ENGINE EMISSION 4-25 CONTROLS

DIESEL ELECTRONIC ENGINE CONTROLS

4-10

DIESEL ENGINE EMISSION CONTROLS

4-29

TROUBLE CODES

4-39

COMPONENT LOCATIONS

3-58

ROUTINE MAINTENANCE AND TUNE-UP

STARTING SYSTEM SENDING UNITS AND SENSORS

ENGINE RECONDITIONING

4-11

CARBURETED ELECTRONIC 4-55 ENGINE CONTROLS

4-17

FUEL INJECTED ELECTRONIC ENGINE CONTROLS

5-2

BASIC FUEL SYSTEM DIAGNOSIS

5-14 MULTI-PORT FUEL INJECTION (MFI)

5-2

FUEL LINE FITTINGS

5-19

CENTRAL SEQUENTIAL FUEL INJECTION (CSFI)

5-22

DIESEL FUEL SYSTEM

5-26

FUEL TANK

5-3

CARBURETED FUEL SYSTEM

5-10

THROTTLE BODY INJECTION (TBI)

6-2

CHASSIS ELECTRICAL 6-7 6-7

VACUUM DIAGRAMS

UNDERSTANDING AND TROUBLESHOOTING ELECTRICAL SYSTEMS BATTERY CABLES

6-13 ENTERTAINMENT SYSTEMS 6-17 WINDSHIELD WIPERS AND WASHERS 6-19 INSTRUMENTS AND SUPPLEMENTAL INFLATABLE SWITCHES RESTRAINT (SIR) SYSTEM 6-22 LIGHTING

6-8

HEATING AND AIR CONDITIONING

6-12

CRUISE CONTROL

6-26

TRAILER WIRING

6-26

CIRCUIT PROTECTION

6-28

WIRING DIAGRAMS

Contents 7-2

MANUAL TRANSMISSION

7-9

7-4

CLUTCH

7-6

AUTOMATIC TRANSMISSION 7-16

7-13

7-8

TRANSFER CASE

DRIVELINE SOLID FRONT DRIVE AXLE INDEPENDENT FRONT DRIVE AXLE

7-19

REAR AXLE

K-SERIES 4WD FRONT . SUSPENSION

8-2

WHEELS

8-18

8-4

C AND R SERIES 2WD FRONT SUSPENSION

8-24

C3HD FRONT SUSPENSION

8-26

REAR SUSPENSION

8-30

STEERING

8-14

V-SERIES 4WD FRONT SUSPENSION

9-2

BRAKE OPERATING SYSTEM

9-6 9-12

DISC BRAKES DRUM BRAKES

9-18

PARKING BRAKE

10-2

EXTERIOR

10-15 GLOSSARY

10-19 MASTER INDEX

9-20

FOUR WHEEL ANTI-LOCK BRAKE SYSTEM

9"25

REAR WHEEL ANTI-LOCK (RWAL) BRAKE SYSTEM

10-5

INTERIOR

SUSPENSION AND STEERING

SAFETY NOTICE

Proper service and repair procedures are vital to the safe, re iable operation of all motor vehicles, as well as the personal safety of those performing repairs. This manual outlines procedures for servicing and repairing vehicles using safe, effective methods. The procedures contain many NOTES, CAUTIONS and WARNINGS which should be followed, along with standard procedures to eliminate the possibility of personal injury or improper service which could damage the vehicle or compromise its safety. It is important to note that repair procedures and techniquesM tools and parts for servicing motor vehicles, as well as the skill and experience of the individual performing the work vary widely. It is not possibles to anticipate all of the conceivable ways or conditions under which vehicles may be serviced, or to provide cautions as to all possible hazards ttiÂŁt may result. Standard and accepted safety precautions and equipment should be used when handling toxic or flammable fluids, and safety goggles or other protection should be used during cutting, grinding, chiseling, prying. or any other process that can cause mate/ial removal or projectiles. Some procedures require the use of tools specially designed for a specific purpose. Before substituting another tool or procedure, you must be completely satisfied that neither your personal safety, nor the performance of the vehicle will be endangered. Although information in this manual is based on industry sojurces and is complete as possible at the time of publication, the possibility exists that some car manufacturers made later changes which could, inot be included here. While striving for total accuracy, the authors or publishers cannot assume responsibility for any errors, changes or omissions that may occur in the compilation of this data.

PART NUMBERS

Part numbers listed in this reference are not recommendat ons by Haynes North America, Inc. for any product brand name. They are references that can be used with interchange manuals and afterm rket supplier catalogs to locate each brand supplier's discrete part number.

SPECIAL TOOLS

Special tools are recommended by the vehicle manufacturer o perform their specific job. Use has been kept to a minimum, but where absolutely necessary, they are referred to in the text by the part lumber of the tool manufacturer. These tools can be purchased, under the appropriate part number, from your local dealer or regional distributo , or an equivalent tool can be purchased locally from a tool supplier or parts outlet. Before substituting any tool for the one recommended, readl the SAFETY NOTICE at the top of this page.

ACKNOWLEDGMENTS

Portions of materials contained herein have been reprints J with the permission of General Motors Corporation, Service Technology Group.

All rights reserved. No part of this book may be reproduce! or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording or by any information storage >r retrieval system, without permission in writing from the copyright holder. While every attempt is made to ensure that the information in this manual is correct, no liability can be accepted by the authors or publishers for loss, damage or injury caused by any errors in, or omissions from, the information given.

HOW TO USE THIS BOOK 1-2

WHERE TO BEGIN 1-2 AVOIDING TROUBLE 1-2 MAINTENANCE OR REPAIR? 1-2 AVOIDING THE MOST COMMON MISTAKES 1-2 TOOLS AND EQUIPMENT 1-2

SPECIAL TOOLS 1-4 SERVICING YOUR VEHICLE SAFELY 1-4

DO'S 1-4 DONTS 1-5 FASTENERS, MEASUREMENTS AND CONVERSIONS 1-5

BOLTS, NUTS AND OTHER THREADED RETAINERS 1-5 TORQUE 1-6 TORQUE WRENCHES 1-6 TORQUE ANGLE METERS 1-7 STANDARD AND METRIC MEASUREMENTS 1-7 SERIAL NUMBER IDENTIFICATION 1-7 VEHICLE 1-7 ENGINE 1-7 TRANSMISSION 1-8 DRIVE AXLE 1-8 TRANSFER CASE 1-8 SERVICE PARTS IDENTIFICATION LABEL 1-10 ROUTINE MAINTENANCE AND TUNE-UP 1-10 AIR CLEANER 1-10 REMOVAL & INSTALLATION 1-13 FUEL FILTER 1-13 REMOVAL & INSTALLATION 1-13 PCVVALVE 1-15 REMOVAL & INSTALLATION 1-15 CRANKCASE DEPRESSION REGULATOR AND FLOW CONTROL VALVE 1-16 SERVICING 1-16 EVAPORATIVE CANISTER 1-16 SERVICING 1-16 BATTERY 1-16 PRECAUTIONS 1-16 GENERAL MAINTENANCE 1-16 BATTERY FLUID 1-17 CABLES 1-17 CHARGING 1-18 REPLACEMENT 1-18 BELTS 1-18 INSPECTION 1-18 ADJUSTMENT 1-18 REMOVAL & INSTALLATION 1-19 BELT ROUTING 1-20 HOSES 1-23 INSPECTION 1-23 REMOVAL & INSTALLATION 1-23 CV-BOOTS 1-24 INSPECTION 1-24 SPARKPLUGS 1-25 SPARK PLUG HEAT RANGE 1-25 REMOVAL & INSTALLATION 1-25 INSPECTION & GAPPING 1-26 SPARK PLUG WIRES 1-27 TESTING 1-27 REMOVAL & INSTALLATION 1-27 DISTRIBUTOR CAP AND ROTOR 1-27 REMOVAL & INSTALLATION 1-27 INSPECTION 1-28 IGNITION TIMING 1-28 GENERAL INFORMATION 1-28 CHECKING & ADJUSTMENT 1-29 VALVE LASH 1-29 ADJUSTMENT 1-29 IDLE SPEED AND MIXTURE ADJUSTMENTS 1-30 CARBURETED ENGINES 1-30 GASOLINE FUEL INJECTED ENGINES 1-30 DIESEL ENGINES 1-31 AIR CONDITIONING SYSTEM 1-32 SYSTEM SERVICE S REPAIR 1-32 PREVENTIVE MAINTENANCE 1-32 SYSTEM INSPECTION 1-32 WINDSHIELD WIPERS 1-33 ELEMENT (REFILL) CARE & REPLACEMENT 1-33 TIRES AND WHEELS 1-33 TIRE ROTATION 1-33 TIRE DESIGN 1-34 TIRE STORAGE 1-34 INFLATIONS INSPECTION 1-34

FLUIDS AND LUBRICANTS

1-35

FLUID DISPOSAL 1-35 FUEL AND OIL RECOMMENDATIONS 1-35 OIL 1-35 FUEL 1-36 ENGINE 1-37 OIL LEVEL CHECK 1-37 OILS FILTER CHANGE 1-37 MANUAL TRANSMISSION 1-38 FLUID RECOMMENDATION 1-38 LEVEL CHECK 1-38 DRAINS REFILL 1-39 AUTOMATIC TRANSMISSION 1-39 FLUID RECOMMENDATIONS 1-39 LEVEL CHECK 1-39 DRAINS REFILL 1-39 TRANSFER CASE 1-40 FLUID RECOMMENDATIONS 1-40 LEVEL CHECK 1-40 DRAINS REFILL 1-40 FRONT AND REAR DRIVE AXLES 1-40 FLUID RECOMMENDATIONS 1-40 LEVEL CHECK 1-40 DRAINS REFILL 1-41 COOLING SYSTEM 1-41 FLUID RECOMMENDATIONS 1-41 LEVEL CHECK 1-42 DRAINING S FLUSHING 1-42 BRAKE MASTER CYLINDER 1-42 FLUID RECOMMENDATIONS 1-42 LEVEL CHECK 1-42 CLUTCH MASTER CYLINDER 1-43 FLUID RECOMMENDATIONS 1-43 LEVEL CHECK 1-43 POWER STEERING PUMP 1-43 FLUID RECOMMENDATION 1-43 LEVEL CHECK 1-43 STEERING GEAR 1-43 FLUID RECOMMENDATIONS 1-43 LEVEL CHECK 1-44 CHASSIS GREASING 1-44 BODY LUBRICATION AND MAINTENANCE 1-45 LOCK CYLINDERS 1-45 HOOD LATCH S HINGES 1-45 DOOR HINGES 1-45 BODY DRAIN HOLES 1-46 FRONT WHEEL BEARINGS 1-46 TRAILER TOWING 1-46 GENERAL RECOMMENDATIONS 1-46 TRAILER WEIGHT 1-46 HITCH (TONGUE) WEIGHT 1-46 ENGINE 1-47 TRANSMISSION 1-47 HANDLING A TRAILER 1-47 JUMP STARTING A DEAD BATTERY 1-47 JUMP STARTING PRECAUTIONS 1-47 JUMP STARTING PROCEDURE 1-47 SINGLE BATTERY GASOLINE AND DIESEL ENGINE MODELS 1-47 DUAL BATTERY DIESEL MODELS 1-48 JACKING 1-48 JACKING PRECAUTIONS 1-49 MAINTENANCE INTERVALS 1-50 GENERAL RECOMMENDATIONS 1-50 BUT THE OWNER'S MANUAL IS DIFFERENT? 1-50 BUT THE REPLACEMENT PART IS DIFFERENT? 1-50 IS MY DRIVING "NORMAL" OR "SEVERE"? 1-50 COMPONENT LOCATIONS UNDERHOOD MAINTENANCE COMPONENT LOCATIONS—R-SERIES 1-11 UNDERHOOD MAINTENANCE COMPONENT LOCATIONS—C-SERIES 1-12 SPECIFICATIONS CHARTS VEHICLE IDENTIFICATION CHART 1-8 GENERAL ENGINE SPECIFICATIONS 1-9 GASOLINE TUNE-UP SPECIFICATIONS 1-31 RECOMMENDED LUBRICANTS 1-36 MAINTENANCE SCHEDULES 1-51 CAPACITIES 1-54

GENERAL

HOW TO USE THIS BOOK TOOLS AND EQUIPMENT SERVICING YOUR VEHICLE SAFELY FASTENERS, MEASUREMENTS AND CONVERSIONS SERIAL NUMBER IDENTIFICATION

1-2 1-2 1-4 1-5 1-7

AND TUNE-UP 1-10 FLUIDS AND LUBRICANTS 1-35 TRAILER TOWING 1-46 iTARTING A DEAD BATTERY 1-47 JACKING 1-48 MAINTENANCE INTERVALS 1-50

1-2

GENERAL INFORMATION AND MAINTENANCE

HOW TO USE THIS BOOK This Chilton's Total Car Care manual for 1988-981/2, % and 1 ton Chevrolet and GMC Pick-ups, Blazers, Jimmys, Tahoes, Yukons and Suburbans is intended to help you learn more about the inner workings of your vehicle, while saving you money on its upkeep and operation. The beginning of the book will likely be referred to the most, since that is where you will find information for maintenance and tune-up. The other sections deal with the more complex systems of your vehicle. Systems (from engine through brakes) are covered to the extent that the average do-it-yourselft r can attempt. This book will not explain such things as rebuilding a different! I because the expertise required and the special tools necessary make thi; uneconomical. It will, however, give you detailed instructions to help you chan je your own brake pads and shoes, replace spark plugs, and perform many morj jobs that can save you money and help avoid expensive problems. A secondary purpose of this book is a reference for owners who want to understand their vehicle and/or their mechanics better.

Where to Begin Before removing any bolts, read through the entire procedure. This will give you the overall view of what tools and supplies will be required. So read, ahead and plan ahead. Each operation should be approached logically and all procedures thoroughly understood before attempting any work. If repair of a component is not considered practical, we tell you how b remove the part and then how to install the new or rebuilt replacement. l(i this way, you at least save labor costs.

Avoiding Trouble Many procedures in this book require you to "label and d i s c o n n e c t . . . " a group of lines, hoses or wires. Don't be think you can remember where (verything goes—you won't. If you hook up vacuum or fuel lines incorrectly,! he vehicle may run poorly, if at all. If you hook up electrical wiring incorrec ly, you may instantly learn a very expensive lesson. You don't need to know the proper name for each hose or line. A pied j of masking tape on the hose and a piece on its fitting will allow you to ass jn your own label. As long as you remember your own code, the lines can be rel onnected by matching your tags. Remember that tape will dissolve in gasaine or solvents; if a part is to be washed or cleaned, use another method of idq itification. A permanent felt-tipped marker or a metal scribe can be very hand; for marking metal parts. Remove any tape or paper labels after assembly.

Maintenance or Repair: Maintenance includes routine inspections, adjustments, and replacertent of parts which show signs of normal wear. Maintenance compensates for wsar or deterioration. Repair implies that something has broken or is not workinji. A need for a repair is often caused by lack of maintenance, for example: dit lining and refilling automatic transmission fluid is maintenance recommended it specific intervals. Failure to do this can shorten the life of the transmission/ transaxle, requiring very expensive repairs. While no maintenance progm.m can prevent items from eventually breaking or wearing out, a general rule is |rue: MAINTENANCE IS CHEAPER THAN REPAIR.

Two basic mechanic's rules should be mentioned here. First, whenever the left side of the vehicle or engine is referred to, it means the driver's side. Conversely, the right side of the vehicle means the passenger's side. Second, screws and bolts are removed by turning counterclockwise, and tightened by turning clockwise unless specifically noted. Safety is always the most important rule. Constantly be aware of the dangers involved in working on an automobile and take the proper precautions. Please refer to the information in this section regarding SERVICING YOUR VEHICLE SAFELY and the SAFETY NOTICE on the acknowledgment page.

Avoiding the Most Common Mistakes Pay attention to the instructions provided. There are 3 common mistakes in mechanical work: 1. Incorrect order of assembly, disassembly or adjustment. When taking something apart or putting it together, performing steps in the wrong order usually just costs you extra time; however, it CAN break something. Read the entire procedure before beginning. Perform everything in the order in which the instructions say you should, even if you can't see a reason for it. When you're taking apart something that is very intricate, you might want to draw a picture of how it looks when assembled in order to make sure you get everything back in its proper position. When making adjustments, perform them in the proper order. One adjustment possibly will affect another. 2. Overtorquing (or undertorquing). While it is more common for overtcrquing to cause damage, undertorquing may allow a fastener to vibrate loose causing serious damage. Especially when dealing with aluminum parts, pay attention to torque specifications and utilize a torque wrench in assembly. If a torque figure is not available, remember that if you are using the right tool to perform the job, you will probably not have to strain yourself to get a fastener tight enough. The pitch of most threads is so slight that the tension you put on the wrench will be multiplied many times in actual force on what you are tightening. There are many commercial products available for ensuring that fasteners won't come loose, even if they are not torqued just right (a very common brand is Loctite"). If you're worried about getting something together tight enough to hold, but loose enough to avoid mechanical damage during assembly, one of trese products might offer substantial insurance. Before choosing a threadlockirg compound, read the label on the package and make sure the product is compatible with the materials, fluids, etc. involved. 3. Crossthreading. This occurs when a part such as a bolt is screwed into a nut or casting at the wrong angle and forced. Crossthreading is more likely to occur if access is difficult. It helps to clean and lubricate fasteners, then to start threading the bolt, spark plug, etc. with your fingers. I! you encounter resistance, unscrew the part and start over again at a different angle until it can be irserted and turned several times without much effort. Keep in mind that many parts have tapered threads, so that gentle turning will automatically bring the part you're threading to the proper angle. Don't put a wrench on the part until it's been tightened a couple of turns by hand. If you suddenly encounter resistance, and the part has not seated fully, don't force it. Pull it back out to make sure it's clean and threading properly. Be sure to take your time and be patient, and always plan ahead. Allow yourself ample time to perform repairs and maintenance.

TOOLS AND EQUIPMENT I See Figures 1 thru 15 Without the proper tools and equipment it is impossible to properly service your vehicle. It would be virtually impossible to catalog every tool that you would need to perform all of the operations in this book. It would be unwise for the amateur to rush out and buy an expensive set of tools on the theory (hat he/she may need one or more of them at some time. The best approach is to proceed slowly, gathering a good quality set of those tools that are used most frequently. Don't be misled by the low cost of bargain tools. It is far better to spend a little more for better quality. Forged wrenches, 6 or 12-point sockets and fine tooth ratchets are by far preferable to their less expensive counterparts. As any good mechanic can tell yoM, there are few worse experiences than trying to work on a vehicle with bad torjls.

Your monetary savings will be far outweighed by frustration and mangled knuckles. Begin accumulating those tools that are used most frequently: those associated with routine maintenance and tune-up. In addition to the normal assortment of screwdrivers and pliers, you should have the following tools: • Wrenches/sockets and combination open end/box end wrenches in sizes 1/8-3/4 in. and/or 3mm-19mm 13/ie in. or % in. spark plug socket (depending on plug type). •"If possible, buy various length socket drive extensions. Universaljoint and wobble extensions can be extremely useful, but be careful when using them, as they can change the amount of torque applied to the socket.

GENERAL INFORMATION AND MAINTENANCE • Jackstands (or support. • Oil filter wrench. • Spout or funnel for pouring fluids. • Grease gun for chassis lubrication (unless your vehicle is not equipped with any grease fittings) • Hydrometer for checking the battery (unless equipped with a sealed, maintenance-free battery). • A container for draining oil and other fluids. • Rags for wiping up the inevitable mess. In addition to the above items there are several others that are not absolutely necessary, but handy to have around. These include an equivalent oil absorbent gravel, like cat litter, and the usual supply of lubricants, antifreeze and fluids. This is a basic list for routine maintenance, but only your personal needs and desire can accurately determine your list of tools. After performing a few projects on the vehicle, you'll be amazed at the other tools and non-tools on your workbench. Some useful household items are: a large turkey baster or siphon, empty coffee cans and ice trays (to store parts), a

1-3

ball of twine, electrical tape for wiring, small rolls of colored tape for tagging lines or hoses, markers and pens, a note pad, golf tees (for plugging vacuum lines), metal coat hangers or a roll of mechanic's wire (to hold things out of the way), dental pick or similar long, pointed probe, a strong magnet, and a small mirror (to see into recesses and under manifolds). A more advanced set of tools, suitable for tune-up work, can be drawn up easily. While the tools are slightly more sophisticated, they need not be outrageously expensive. There are several inexpensive tach/dwell meters on the market that are every bit as good for the average mechanic as a professional model. Just be sure that it goes to a least 1200-1500 rpm on the tach scale and-that it works on 4, 6 and 8-cylinder engines. The key to these purchases is to make them with an eye towards adaptability and wide range. A basic list of tune-up tools could include: • Tach/dwell meter. • Spark plug wrench and gapping tool. • Feeler gauges for valve adjustment. • Timing light.

,SS«*»8i

Fig. 1 All but the most basic procedures will require an assortment of ratchets and sockets

Fig. 2 In addition to ratchets, a good set of wrenches and hex keys will be necessary

Fig. 3 A hydraulic floor jack and a set of jackstands are essential for lifting and supporting the vehicle

Fig. 5 Various drivers, chisels and prybars are great tools to have in your toolbox

Fig. 6 Many repairs will require the use of a torque wrench to assure the components are properly fastened

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Fig. 4 An assortment of pliers, grippers and cutters will be handy for old rusted parts and stripped bolt heads

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'''"^Mlf

Fig. 7 Although not always necessary, using specialized brake tools will save time

Fig. 8 A few inexpensive lubrication tools will make maintenance easier

Fig. 9 Various pullers, clamps and separator tools are needed for many larger, more complicated repairs

1-4

GENERAL INFORMATION AND MAINTENANCE

r / vrr*>fes»

^ Fig. 10 A variety of tools and gauges should be used for spark plug gapping and installation

Fig. 11 ina ictive type timing light

Fig. 13 A vacuum/pressure tester is necessary for many testing procedures

Fig. 14 M( st modern automotive multimeters incorporate many helpful features

TCCX1POG

The choice of a timing light should be made carefully. A light which vorks on the DC current supplied by the vehicle's battery is the best choice; it mould have a xenon tube for brightness. On any vehicle with an electronic ignit in system, a timing light with an inductive pickup that clamps around the No. | spark plug cable is preferred. In addition to these basic tools, there are several other tools and gaut :syou may find useful. These include: • Compression gauge. The screw-in type is slower to use, but e!imii(jates the possibility of a faulty reading due to escaping pressure. • Manifold vacuum gauge. • 12V test light. • A combination volt/ohmmeter • Induction Ammeter. This is used for determining whether or not thdre is current in a wire. These are handy for use if a wire is broken somewhere! n a wiring harness. As a final note, you will probably find a torque wrench necessary for; II but the most basic work. The beam type models are perfectly adequate, althd jgh the

TCCX1P02

Fig. 12 A screw-in type compression gauge is recommended for compression testing

Fig. 15 Proper information is vital, so always have a Chilton Total Car Care manual handy

newer click types (breakaway) are easier to use. The click type torque wrenches tend to be more expensive. Also keep in mind that all types of torque wrenches should be periodically checked and/or recalibrated. You will have to decide for yourself which better fits your pocketbook, and purpose.

Special Tools Normally, the use of special factory tools is avoided for repair procedures, since these are not readily available for the do-it-yourself mechanic. When it is possible to perform the job with more commonly available tools, it will be pointed out, but occasionally, a special tool was designed to perform a specific function and should be used. Before substituting another tool, you should be convinced that neither your safety nor the performance of the vehicle will be ccmpromised. Special tools can usually be purchased from an automotive parts store or from your dealer. In some cases special tools may be available directly from the tool manufacturer.

SERVICING YOUR VEHICLE SAFELY » See Figures 16,17 and 18 It is virtually impossible to anticipate all of the hazards involved with autt motive maintenance and service, but care and common sense will prevent most accidents. The rules of safety for mechanics range from "don't smoke around gaioline," to "use the proper tool(s) for the job." The trick to avoiding injuries is to develop safe work habits and to take every possible precaution.

• Do keep a fire extinguisher and first aid kit handy. • Do wear safety glasses or goggles when cutting, drilling, grinding or prying, even if you have 20-20 vision. If you wear glasses for the sake of v sion, wear safety goggles over your regular glasses.

• Do shield your eyes whenever you work around the battery. Batteries contain sulfuric acid. In case of contact with, flush the area with water or a mixture of water and baking soda, then seek immediate medical attention. • Do use safety stands (jackstands) for any undervehicle service. Jacks are for raising vehicles; jackstands are for making sure the vehicle stays raised until you want it to come down. • Do use adequate ventilation when working with any chemicals or hazardous materials. Like carbon monoxide, the asbestos dust resulting from some brake lining wear can be hazardous in sufficient quantities. • Do disconnect the negative battery cable when working on the electrical system. The secondary ignition system contains EXTREMELY HIGH VOLTAGE. In some cases it can even exceed 50,000 volts. • Do follow manufacturer's-directions whenever working with potentially hazardous materials. Most chemicals and fluids are poisonous.

GENERAL INFORMATION AND MAINTENANCE

f*1

1-5

TCCS1020

Fig. 16 Screwdrivers should be kept in good condition to prevent injury or damage which could result if the blade slips from the screw

Fig. 17 Using the correct size wrench will help prevent the possibility of rounding off a nut

• Do properly maintain your tools. Loose hammerheads, mushroomed punches and chisels, frayed or poorly grounded electrical cords, excessively worn screwdrivers, spread wrenches (open end), cracked sockets, slipping ratchets, or faulty droplight sockets can cause accidents. • Likewise, keep your tools clean; a greasy wrench can slip off a bolt head, ruining the bolt and often harming your knuckles in the process. • Do use the proper size and type of tool for the job at hand. Do select a wrench or socket that fits the nut or bolt. The wrench or socket should sit straight, not cocked. • Do, when possible, pull on a wrench handle rather than push on it, and adjust your stance to prevent a fall. • Do be sure that adjustable wrenches are tightly closed on the nut or bolt and pulled so that the force is on the side of the fixed jaw. • Do strike squarely with a hammer; avoid glancing blows. • Do set the parking brake and block the drive wheels if the work requires a running engine.

Don'ts • Don't run the engine in a garage or anywhere else without proper ventilation—EVER! Carbon monoxide is poisonous; it takes a long time to leave the human body and you can build up a deadly supply of it in your system by simply breathing in a little at a time. You may not realize you are slowly poisoning yourself. Always use power vents, windows, fans and/or open the garage door. • Don't work around moving parts while wearing loose clothing. Short sleeves are much safer than long, loose sleeves. Hard-toed shoes with neoprene

Fig. 18 NEVER work under a vehicle unless it is supported using safety stands (jackstands)

soles protect your toes and give a better grip on slippery surfaces. Watches and jewelry is not safe working around a vehicle. Long hair should be tied back under a hat or cap. • Don't use pockets for toolboxes. A fall or bump can drive a screwdriver deep into your body. Even a rag hanging from your back pocket can wrap around a spinning shaft or fan. • Don't smoke when working around gasoline, cleaning solvent or other flammable material. • Don't smoke when working around the battery. When the battery is being charged, it gives off explosive hydrogen gas. • Don't use gasoline to wash your hands; there are excellent soaps available. Gasoline contains dangerous additives which can enter the body through a cut or through your pores. Gasoline also removes all the natural oils from the skin so that bone dry hands will suck up oil and grease. • Don't service the air conditioning system unless you are equipped with the necessary tools and training. When liquid or compressed gas refrigerant is released to atmospheric pressure it will absorb heat from whatever it contacts. This will chill or freeze anything it touches. • Don't use screwdrivers for anything other than driving screws! A screwdriver used as an prying tool can snap when you least expect it, causing injuries. At the very least, you'll ruin a good screwdriver. • Don't use an emergency jack (that little ratchet, scissors, or pantograph jack supplied with the vehicle) for anything other than changing a flat! These jacks are only intended for emergency use out on the road; they are NOT designed as a maintenance tool. If you are serious about maintaining your vehicle yourself, invest in a hydraulic floor jack of at least a 11/2 ton capacity, and at least two sturdy jackstands.

FASTENERS, MEASUREMENTS AND CONVERSIONS

Bolts, Nuts and Other Threaded Retainers » See Figures 19 and 20

Although there are a great variety of fasteners found in the modern car or truck, the most commonly used retainer is the threaded fastener (nuts, bolts, screws, studs, etc.). Most threaded retainers may be reused, provided that they are not damaged in use or during the repair. Some retainers (such as stretch bolts or torque prevailing nuts) are designed to deform when tightened or in use and should not be reinstalled. Whenever possible, we will note any special retainers which should be replaced during a procedure. But you should always inspect the condition of a retainer when it is removed and replace any that show signs of damage. Check all threads for rust or corrosion which can increase the torque necessary to achieve the desired clamp load for which that fastener was originally selected. Additionally, be sure that the driver surface of the fastener has not been compromised by rounding or other damage. In some cases a driver surface may become only partially rounded, allowing the driver to catch in only one direction. In many of these occurrences, a fastener may be installed and tightened, but the driver would not be able to grip and loosen the fastener again. If you must replace a fastener, whether due to design or damage, you must ALWAYS be sure to use the proper replacement. In all cases, a retainer of the

LOCKWASHERS

CO)

•HI

• TCCS1036

Fig. 19 There are many different types of threaded retainers found on vehicles

1-6

GENERAL INFORMATION AND MAINTENANCE h-c —i i

F ^^HI i (.

r A

^ r^=====^^$A=sf~ —1 '! Z i

DEFLECTING BEAM

—-S—-*~~—?^^r~~

& o ,

—

' ] k J > y x ^

A - Length B - Diameter (major diameter) C - Threads per inch or mm

r— E —«1

E - Size of the wrench required F - Root diameter (minor diameter)

(n ] o

fe'JH--'

s'.1,1,1,' 't\ i

same design, material and strength should be used. Markings on the he|ds of most bolts will help determine the proper strength of the fastener. The saj ne material, thread and pitch must be selected to assure proper installation nd safe operation of the vehicle afterwards. Thread gauges are available to help measure a bolt or stud's thread. l|ost automotive and hardware stores keep gauges available to help you selec the proper size. In a pinch, you can use another nut or bolt for a thread gauc;. If the bolt you are replacing is not too badly damaged, you can select a match iy finding another bolt which will thread in its place. If you find a nut which threads properly onto the damaged bolt, then use that nut to help select he replacement bolt.

••-••' WARNING Be aware that when you find a bolt with damaged threads, you may also find the nut or drilled hole it was threaded into has also teen damaged. If this is the case, you may have to drill and tap thd hole, replace the nut or otherwise repair the threads. NEVER try to I irce a replacement bolt to fit into the damaged threads.

Torque Torque is defined as the measurement of resistance to turning or rotat ig. tends to twist a body about an axis of rotation. A common example of thi would be tightening a threaded retainer such as a nut, bolt or screw. Mee ;uring torque is one of the most common ways to help assure that a threaded retainer has been properly fastened. When tightening a threaded fastener, torque is applied in three distinc areas, the head, the bearing surface and the clamp load. About 50 percent of thi measured torque is used in overcoming bearing friction. This is the friction b tween the bearing surface of the bolt head, screw head or nut face and the base naterial or washer (the surface on which the fastener is rotating). Approximate 140 percent of the applied torque is used in overcoming thread friction. This laves only about 10 percent of the applied torque to develop a useful clamp IDE i (the force which holds a joint together). This means that friction can account 'pr as much as 90 percent of the applied torque on a fastener.

1 CLICK TYPE

TCCS1038

Fig. 20 Threaded retainer sizes are determined using these me surements

TCCS1015

Fig. 21 Various styles of torque wrenches are usually available at your local automotive supply store Click (Breakaway) Type Another popular design of torque wrench is the click type. To use the click type wrench you pre-adjust it to a torque setting. Once the torque is reached, the wrench has a reflex signaling feature that causes a momentary breakaway of the torque wrench body, sending an impulse to the operator's hand. Pivot Head Type I See Figure 22 Some torque wrenches (usually of the click type) may be equipped with a pivot head which can allow it to be used in areas of limited access. BUT, it must be used properly. To hold a pivot head wrench, grasp the handle lightly, and as you pull on the handle, it should be floated on the pivot point. If the handle comes in contact with the yoke extension during the process of pulling, there is a very good chance the torque readings will be inaccurate because this could alter the wrench loading point. The design of the handle is usually such as to make it inconvenient to deliberately misuse the wrench. ••It should be mentioned that the use of any U-joint, wobble or extension will have an effect on the torque readings, no matter what type of wrench you are using. For the most accurate readings, install the socket directly on the wrench driver. If necessary, straight extensions (which hold a socket directly under the wrench driver) will have the least effect on the torque reading. Avoid any extension that alters the length of the wrench from the handle to the head/driving point (such as a crow's foot). U-joint or wobble extensions can greatly affect the readings; avoid their use at all times.

TORQUE WRENCHES I See Figure 21 In most applications, a torque wrench can be used to assure proper installation of a fastener. Torque wrenches come in various designs and most auDmotive supply stores will carry a variety to suit your needs. A torque wrench should be used any time we supply a specific torque value for a fastener. Again, the general rule of "if you are using the right tool for the job, you should not have to strain to tighten a fastener" applies here. Beam Type The beam type torque wrench is one of the most popular types. It cons sts of a pointer attached to the head that runs the length of the flexible beam (srpft) to a scale located near the handle. As the wrench is pulled, the beam bends fnd the pointer indicates the torque using the scale.

PIVOTED

HANDLE

TORQUE WRENCH TCCS1041

Fig. 22 Torque wrenches with pivoting heads must be grasped and used properly to prevent an incorrect reading Rigid Case (Direct Reading) A rigid case or direct reading torque wrench is equipped with a dial indicator to show torque values. One advantage of these wrenches is that they can be held at any position on the wrench without affecting accuracy. These wrenches are often preferred because they tend to be compact, easy to read and have a great degree of accuracy.

GENERAL INFORMATION AND MAINTENANCE TORQUE ANGLE METERS Because the frictional characteristics of each fastener or threaded hole will vary, clamp loads which are based strictly on torque will vary as well. In most applications, this variance is not significant enough to cause worry. But, in certain applications, a manufacturer's engineers may determine that more precise clamp toads are necessary (such is the case with many aluminum cylinder heads). In these cases, a torque angle method of installation would be specified. When installing fasteners which are torque angle tightened, a predetermined seating torque and standard torque wrench are usually used first to remove any compliance from the joint. The fastener is then tightened the specified additional portion of a turn measured in degrees. A torque angle gauge (mechanical protractor) is used for these applications.

CONVERSION FACTORS LENGTH-DISTANCE Inches (m ) Fee!

x 25,4

(ft.)

= Inches

x 3.281

= Kilometers (km)

r--- Feet

x .0621

= Miles

VOLUME Cubic Inches (in3) IMP Pints (IMP

x 16.387

x .061

= m3

= Liters (t.)

x 1 76

x 1.137

= Liters (L)

x .88

= IMPqt

IMP Gallons (IMP gall

x 4..S46

- Liters (L)

x .22

= IMPgai.

IMP Quails (IMP qt.)

<t 1.201

= US Quarts (US qi.)

x .833

- IMP qt.

IMP Gallons (IMP gal.)

x 1.201

= US Gallons (US gal.)

x 831

= IMP gal.

x 29.573

-= Milliliters

x 034

US Pints (US pi >

x .473

= Liters (L)

x 2.113

US Quarts (US 4i )

x .946

- Liters (L)

x 1.057

pt |

= Cubic Centimeters

x .56S

IMP Quarts (IMPqt )

Ounces

x 3 7X5

- Liters (L)

= IMP pi.

= Ounces = Pints - Quarts

x 264

= Gallons

x .035

« Ounces

MASS-WEIGHT Ounces (oz I

* 28.35

= Grams (g)

x 454

= Kilograms (kg)

= Pounds

x 2 205

PRESSURE Pounds Pei Sq. In (psi)

Throughout this manual, specifications are given to help you determine the condition of various components on your vehicle, or to assist you in their installation. Some of the most common measurements include length (in. or cm/mm), torque (ft. Ibs., inch Ibs. or Nm) and pressure (psi, in. Hg, kPa or mm Hg). In most cases, we strive to provide the proper measurement as determined by the manufacturer's engineers. Though, in some cases, that value may not be conveniently measured with what is available in your toolbox. Luckily, many of the measuring devices which are available today will have two scales so the Standard or Metric measurements may easily be taken. If any of the various measuring tools which are available to you do not contain the same scale as listed in the specifications, use the accompanying conversion factors to determine the proper value. The conversion factor chart is used by taking the given specification and multiplying it by the necessary conversion factor. For instance, looking at the first line, if you have a measurement in inches such as "free-play should be 2 in." but your ruler reads only in millimeters, multiply 2 in. by the conversion factor of 25.4 to get the metric equivalent of 50.8mm. Likewise, if the specification was given only in a Metric measurement, for example in Newton Meters (Nm), then look at the center column first. If the measurement is 100 Nm, multiply it by the conversion factor of 0.738 to get 73.8 ft. Ibs.

x .0394

= Meters (m)

x ! 604

Pounds (Ib.)

» See Figure 23

= Millimeters (mm)

x 305

Miles

US Gallons (US g.,1.)

Standard and Metric Measurements

1-7

x 6.895

Inches of Mercury (Hg)

*= Kilopascals (kPa)

x 4912

= psi

x .145

-- psi

x 2.036

x .07355

- Inches of Mercury

x 13783

Inches of Water (H,O)

x .03613

=. psi

x 27.684

Inches of Water (H.O)

x .248

= Kilopascals (kPa)

x4026

= Hg = Hg = H,O - H.O = H,0

x . 1 13

= Newton Meters (N-m)

x 8.85

= in-lb

x 1 356

= Newton Meters (N-m)

x .738

. ft-lb

x 1 .609

= Kilometers Per Hour (KPH)

x .621

- MPH

Inches of Mercury (Hg)

x 3.377

Inches of Water (HjO)

=-- Kilopascals (kPa)

x .2961

TORQUE Pounds-Force Inches (in-lh) Pounds-Force Feet (ft-lh)

VELOCITY Miles Per Hour (MPH I

POWER Horsepower (Hp(

* .745

=-- Kilowatts

= Horsepower

x 1 34

FUEL CONSUMPTION* Miles Per Gallon IMP (MPG)

x .154

Kilometers Per Liter (Km/L)

x 2.352

- IMP MPG

Kilometers Per Liter {Km/1,)

x 2.352

= US MPG

- Kilometers Per Liter (Km/L)

•It is common to covert from miles per gallon (r ipg) to liters/100 kilometers (1/100 km), where = 282 and mpg (US) x 1/10(1 km = 235

upg (IMP) x 1/100

TEMPERATURE Degree Fahrenheit CF) Degree CVUius f(')

- f C x l . 8 ) t 32 -

(°K - 32) \6

TCCS1044

Fig. 23 Standard and metric conversion factors chart

SERIAL NUMBER IDENTIFICATION

Vehicle

> See Figures 24 and 25 The Vehicle Identification Number (VIN) plate is mounted on the driver's side of the instrument panel, and is visible through the windshield. The models covered in this book are full size C/K trucks including the Tahoe, Blazer, Jimmy, Yukon and Suburban. Starting in 1992 the Blazer was renamed the Blazer/Tahoe and Jimmy the Jimmy/Yukon. The 5th digit on the vehicle identification number is the vehicle line and chassis type: • C and R are 2-wheel drive conventional cabs • V and K are 4-wheel drive conventional cabs

Fig. 25 Vehicle Identification Number decoding

Engine »See Figure 26

Fig. 24 The Vehicle Identification Number (VIN) is visible through the windshield

On the 4.8L, inline 6-cylinder engine, the engine identification number is found on a machined pad on the left side of the block, just rear of center, below the engine side cover. On the 1988-92 4.3L V6 engine, the engine identification number is found on a machined pad on the block, at the front just below the right side cylinder head.

1-8

GENERAL INFORMATION AND MAINTENANCE VEHICLE IDENTIFICATION CHART Engine Code Engine Series (IO/VIN) Z W

Engine Displacement Liters

Cubic Inches

No. of Cylinders

Fuel System

263 (4293)

TBI

263 (4293)

CSFI

T H M K R C J

4.3 4.3 4.8 5.0 5.0 5.7 5.7 6.2 6.2

292 (4785)

305 (4999)

1BC ®

305 (4999)

CSFI

350 (5735)

TBI

350 (5735)

CSFI

379(6210)

379 (6210)

D D

F P S N W J

6.5 6.5 6.5 7.4 7.4 7.4

395 (6473)

8 8 8 8

454 (7440) 454 (7440) 454 (7440)

Model Year

Eng. Mfg. CPC

Code J

Year

CPC CPC CPC CPC CPC CPC DDA DDA CPC CPC CPC CPC CPC CPC

K L M N P R S T V W

1989

@ D TD TBI 4BC MFI

1988 1990 1991 1992 1993 1994 1995 1996 1997 1998

The 10th digit of the Vehicle Identification Number (VIN) is the ; ear code and the 8th digit is the engine code. ®4BCorTBI

D-Diesel

® D or TD/HO

DDA-DetroitC sel Allison

1BC-1 Barrel Carburetor

HO-High Oi put

4BC-4 Barrel Carburetor

MFI-Multi-port uel Injection

CPC-Chevrolet/Pontiac ol Canada

TBI-Throttle B^Jy Injection

CSFi-Central Sequential Fuel Injection

TD-Turbo Dii

12—Month of Manufacture (December) 10-Day of Manufacturer (Tenth) T—Truck engine FA—Transmission and Engine Combination

Transmission

Fig. 26 The engine identification number is usually located on < machined pad on the engine block

On the 1993-98 4.3L V6 engine, the engine identification number is f und on a machined pad on the rear of the cylinder block, below and behind t t ; left cylinder head where the engine mates with the bellhousing. On V8 gasoline engines, the engine identification number is usually f pnd on a machined pad on the block, at the front just below the right side cylind head. The engine identification number is sometimes also found on a mat hined pad on the left, rear upper side of the block, where the engine mates with he bellhousing. On V8 diesel engines, the engine identification number is found on a machined pad on the front of the block, between the left cylinder head anf the thermostat housing, and/or on a machined pad on the left rear of the bloc) t, just behind the left cylinder head. In the following example, engine number F1210TFA is broken down as follows: • F—Manufacturing Plant. F-Flint and T-Tonawanda

The Muncie 117mm 4-speed transmission is numbered on the rear of the case, above the output shaft. The 4-Speed 85mm and 5-Speed 85mm transmissions are numbered on the right rear of the case. The NVG 3500 5-speed transmissions are numbered on the top, left side of the case, near the bellhousing. The NVG 4500 5-speed transmissions are numbered on the top, left side of the case, near the bellhousing. The NVG 5LM60 5-speed transmissions are numbered on the lower left side, about halfway back on the case. The automatic transmissions are identified by a plate attached to the right side, which is stamped with the serial number.

Drive Axle The drive axle serial number is stamped on the axle shaft housing, where it connects to the differential housing. Front axles on four wheel drive models are marked on the front of the left axle tube.

Transfer Case All transfer cases have a build tag attached to the case. On the NP205, it is attached to the bolt retaining the Power Take Off (PTO) cover.

GENERAL INFORMATION AND MAINTENANCE

»e

8 _ 33

ill u- S,f

111

s 3,

e -h T—

o _, o

ill

Silll

1-9

1-10

GENERAL INFORMATION AND MAINTENANCE

On the NP231, NP233 and NP241, it is attached to the rear case half. On the NV241 and NV243, it is attached to the rear case half. On the Borg Warner 4401/4470, it is attached to an extension housing bolt.

Service Parts Identification Label I See Figure 27 The service parts identification label, commonly known as the optio i list, is usually located on the inside of the glove compartment door. On sor IB trucks, you may have to look for it on an inner fender panel. The label ists the vehicle serial number, wheelbase, all Regular Production Options (IPOs) and all special equipment. Probably, the most valuable piece of inform tion on this label is the paint code, a useful item when you have occasion tj need paint.

2 Wheel base 3 Model designation 4 RPO and/Of SEO

5 Order numbef 6 E.lenoi colof 7 Paml lechnology

Fig. 27 Service parts identification label

ROUTINE MAINTENANCE AND TUNE-UP Proper maintenance and tune-up is the key to long and trouble-free v :hicle and look through the filter at the light. If no glow of light can be seen through life. Studies have shown (hat a properly tuned and maintained vehicle a \e better gas mileage than anmaterial, out-of-tune vehicle. As aIfconscientio the element replace the filter. holes in thesfilter element are apparent or signs of dirt seepage through the filter are evident, replace the filter. owner and driver, set aside a Saturday morning, say once a month, to cf ick or replace items which could cause major problems later. Keep your own p rsonal log to jot down which services you performed, how much the parts cost m, the date, and the exact odometer reading at the time. Keep all receipts fo such items as engine oil and filters, so that they may be referred to in case of j elated problems or to determine operating expenses. As a do-it-yourselfer, the:i receipts are the only proof you have that the required maintenance was [ informed. In the event of a warranty problem, these receipts will be invalua; )le. The literature provided with your vehicle when it was originally delivered includes the factory recommended maintenance schedule. If you no Ion; ;r have this literature, replacement copies are usually available from the dealer.

Air Cleaner » See Figures 28, 29 and 30 The element should be replaced at the recommended intervals shown in the Maintenance Intervals chart later in this section. If your truck is operated under severely dusty conditions or severe operating conditions, more frequent changes will certainly be necessary. Inspect the element at least twice a \tear. Early spring and early fall are always good times for inspection. Remove tie element and check for any perforations or tears in the filter. Check the cli aner housing tor signs of dirt or dust that may have leaked through the filter e ement or in through the snorkel tube. Position a droplight on one side of the element

1 2. 3. 4.

1. Wing Nut 2.2 Hole Cover 3. Air Cleaner Assembly 4. Air Cleaner Extension 5. TBI Assembly

Fig. 29 Exploded view of the air cleaner housing—1993 gasoline engines

Air cleaner Seal Extension Stud

5. Nut - 18 ini

\. Air Cleaner

3. EGR Valve

Fig. 28 Typical air cleaner housing assembly components—198 -92 gasoline engines

Fig. 30 Exploded view of the air cleaner housing—6.2L diesel engines

GENERAL INFORMATION AND MAINTENANCE

* LU

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— T3

-a cr

*? — !H .2 ^ _cr a3 ."2 <=n

-o

&'f

1 5feS fe js 1 .a =

O C — — ,— - f«

^ <C 'ra O Q r-~ co CD

Q _

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CD •

Q. ^^

O r^r -~ CD

i_ ,.2

O t_ ,_ co S .32

,_ O ct3 O3 ci O3 .— CJ) CO CC UJ CC <C

1-11

UNDERHOOD MAINTENANCE COMPONENT LOCATIONSâ&#x20AC;&#x201D;C/K-SERIES

1. Engine oil dipstick 2. Automatic transmission dipstick 3. Battery 4. Distributor (under resonance housing)

5. Coolant recovery reservoir

6. Air filter element (under housing) 7. Brake master cylinder 8. Oil filler cap 9. Serpentine belt

10. Radiator hose (upper) 11. Windshield washer fluid reservoir 12. Power steering reservoir 13. Underhood fuse panel 14. Radiator cap

ro CD

O ID

1 CD

GENERAL INFORMATION AND MAINTENANCE

1-13

Fuel Filter

REMOVAL & INSTALLATION I See Figures 31. 32, 33. 34 and 35

REMOVAL & INSTALLATION

1. On older model vehicles, loosen the wingnut(s) and lift off the housing cover. On newer model vehicles, unfasten the retaining clips and separate the two case halves. 2. On the 6.5L diesel, position the cover with the air cleaner flexible hose off to the side. 3. Withdraw the element from the housing and discard it. 4. With a clean rag, remove any dirt or dust from the front cover and also from the element seating surface. To install: 5. Position and install the new filter element so that it seats properly in the housing. 6. On the 6.5L diesel, position the cover with the attached hose over the element and snap the retaining clips into place, 7. On early model vehicles, install the housing lid and tighten the wingnut(s) to about 18 inch Ibs. (2 Nm), 8. On late model vehicles, place the housing cover into position and engage the retaining clip.

WARNING Do not drive the vehicle with air cleaner removed. Doing so will allow dirt and a variety of other foreign particles to enter the engine and cause damage and wear. Also, backfiring could cause a fire in the engine compartment.

Carbureted Gasoline Engines FILTER IN CARBURETOR I See Figure 36 The fuel filter should be serviced at the interval given on the Maintenance Interval chart. Two types of fuel filters are used, a bronze type and a paper element type. Filter replacement should be attempted only when the engine is cold. Additionally, it is a good idea to place some absorbent rags under the fuel fittings to catch the gasoline which will spill out when the lines are loosened. 1. Disengage the fuel line connection at the intake fuel filter nut. Plug the opening to prevent loss of fuel. 2. Remove the intake fuel filter nut from the carburetor with a 1 in open end wrench (or adjustable wrench). 3. Remove the filter element and spring. 4. Check the element for restrictions by blowing on the cone end. Air should pass freely. 5. Clean or replace the element, as necessary. To install: 6. Install the element spring, then the filter element in the carburetor. Bronze filters should have the small section of the cone facing out.

Fig. 31 Loosen the wingnut and remove it from the air cleaner cover

Fig. 32 Removing the air cleaner cover

Fig. 34 On newer vehicles, lift up the air cleaner coverâ&#x20AC;&#x201D;1996 truck shown

Fig. 35 Remove the filter elementâ&#x20AC;&#x201D;1996 truck shown

Fig. 33 Remove the old air cleaner element

87981P05

Fig. 36 In-carburetor fuel filter

1-14

GENERAL INFORMATION AND MAINTENANCE

7. Install a new gasket on the intake fuel nut. Install the nut in the carburetor body and tighten securely. 8. Install the fuel line and tighten the connector. INLINE FILTER

Some trucks may have an inline filter. This is a can-shaped device located in the fuel line between the pump and the carburetor. It may be made of either plastic or metal. To replace the filter: 1. Place some absorbent rags under the filter. Remember, it will be Jill of gasoline when removed. 2. Use a pair of pliers to expand the clamp on one end of the filter, I ji slide the clamp down past the point to which the filter pipe extends in tlpp rubber hose. Do the same with the other clamp. 3. Gently twist and pull the hoses free of the filter pipes. Remove arjjl discard the old filter.

3. Turn the filter housing counterclockwise and allow the fuel to drain into a suitable container. 4. Remove the filter housing and gasket from the base. 5. Remove the fuel filter cartridge. 6. Inspect the filter housing for signs of corrosion or damage, replace as necessary. To install: 7. Appall a few drops of clean engine oil to the new housing gasket and install the gasket. 8. Install a new filter cartridge and the place the filter housing into position. 9. Tighten the housing by turning it clockwise until the gasket seats, then tighten the housing an additional % turn. 10. Connect the negative battery cable. 11. Start the engine and check for fuel leaks. 12. Repair as necessary.

•»Mcst replacement filters come with new hoses that should be installed with a new filter.

Diesel Engines

4. Install the new filter into the hoses, slide the clamps back into pla^e, and check for leaks with the engine idling.

6.2L

Fuel Injected Gasoline Engines EXCEPT CARTRIDGE TYPE » See Figures 37 and 38 The inline filter on the fuel injected models is found along the frame 1. Properly relieve the fuel system pressure.

CAUTION The 220 TBI unit used on the V6 and V8 engines contains a constant bleed feature in the pressure regulator that relieves pressure any time the engine is turned off. Therefore, no special relief procedure is required, however, a small amount of fuel may be released when the fuel line is disconnected. To reduce the chance of personal injury, cover the fuel line with cloth to collect the fuel and then place the cloth in an approved container. 2. Disconnect the fuel lines. 3. Remove the fuel filter from the retainer or mounting bolt. To install: 4. Install the filter and tighten the bolt to 12 ft. Ibs. (16 Nm). Connecj the fuel lines and tighten the nuts to 20 ft. Ibs. (26 Nm). 5. Road test the truck and check for any leaks. •••The filter has an arrow (fuel flow direction) on the side of the c; se, be sure to install it correctly in the system, the with arrow facing aw; from the fuel tank. CARTRIDGE TYPE > See Figure 39 1. Properly relieve the fuel system pressure. 2. Disconnect the negative battery cable.

ENGINE

> See Figures 40 and 41 The fuel/water separator is usually located on the header assembly. 1. Drain the fuel from the fuel filter by opening both the air bleed and the water drain valve allowing the fuel to drain out into an appropriate container. 2. Remove the fuel tank cap to release any pressure or vacuum in the tank. 3. Unstrap both bail wires with a screwdriver and remove the filter. To install: 4. Before installing the new filter, insure that both filter mounting plate fittings are clear of dirt. 5. Install the new filter, snap into place with the bail wires. 6. Close the water drain valve and open the air bleed valve. Connect a Ve in. (3mm) I.D. hose to the air bleed port and place the other end into a suitable container. 7. Disconnect the fuel injection pump shut off solenoid wire. 8. Crank the engine for 10-15 seconds, then wait one minute for the starter motor to cool. Repeat until clear fuel is observed coming from the air bleed. •••If the engine is to be cranked, or starting attempted with the air cleaner removed, care must be taken to prevent dirt from being pulled into the air inlet manifold which could result in engine damage. 9. Close the air bleed valve, reconnect the injection pump solenoid wire and replace the fuel tank cap. 10. Start the engine, allow it to idle for 5 minutes and check the fuel filter for leaks. 6.5L ENGINE I See Figure 42 1. Remove the fuel tank cap to release any pressure or vacuum in the tank. 2. If equipped, remove the upper intake manifold cover. 3. Open the air bleed valve on top of the filter assembly. 4. Spin off the element nut at the top of the filter—it looks like a large knurled knob. 5. Lift the filter element out of the header assembly.

87981P06

Fig. 37 The fuel filter is found along the frame rail

Fig. 38 Using two flare nut wrenches, disconnect thi fuel lines

Fig. 39 The cartridge type fuel filter is located along the frame rail

GENERAL INFORMATION AND MAINTENANCE 1-15 To install: 6. Clean the mating surfaces on the header assembly and the filter. Align the widest key slot in the element cap with that in the header assembly, push the element down until the two surfaces make contact, then tighten the nut by hand. 7. Open the air bleed valve on top of the filter assembly. Connect a hose to the bleeder valve and insert the other end into a suitable glass container. 8. Disconnect the fuel injection pump shut-down solenoid wire or the FUEL SOL relay center fuse (whichever applies to your vehicle, then crank the engine in 10-15 second intervals until clear, clean fuel is coming out of the hose. »»Wait about one minute between cranking intervals!

9. Remove the hose and close the bleeder valve. 10. Connect the shut-down solenoid wire or fuse and install the fuel cap. Start the engine and allow it to idle for a few minutes. Check for leaks. 1 2. 3 4 5

Water drain valve Bail wires Fuel filter element Air bleed Filter adapter

6 7 8 9

Air bleed port Restriction switch Fuel heater Water sensor 84901031

Fig. 40 Exploded view of the fuel filter—6.2L engines

FUEL FILTER/WATER SEPARATOR

FILTER INLET HOSE FUEL FILTE'R/WATER SEPARATOR ^

Fig. 41 Fuel filter/water separator—6.2L engines

7. 8. 9. 0. 1 2 4. 5.

PCV Valve > See Figure 43 "•Diesel engines do not utilize a PCV system. The PCV valve, which is the heart of the positive crankcase ventilation system, should be changed as noted in the Maintenance Intervals chart at the end of this section. The main thing to keep in mind is that the valve should be free of dirt and residue and should be in working order. As long as the valve is not showing signs of becoming damaged or gummed up, it should perform its function properly. When the valve becomes sticky and will not operate freely, it should be replaced. The PCV valve is used to control the rate at which crankcase vapors are returned to the intake manifold. The action of the valve plunger is controlled by intake manifold vacuum and the spring. During deceleration and idle, when manifold vacuum is high, it overcomes the tension of the valve spring and the plunger bottoms in the manifold end of the valve housing. Because of the valve construction, it reduces, but does not stop, the passage of vapors to the intake manifold. When the engine is lightly accelerated or operated at constant speed, spring tension matches intake manifold vacuum pull and the plunger takes a mid-position in the valve body, allowing more vapors to flow into the manifold. The valve is either mounted on the valve cover or in the line which runs from the intake manifold to the crankcase. Do not attempt to adjust or repair the valve. If the valve is faulty, replace it.

NUT. ELEMENT ASSEMBLY, ELEMENT ASSEMBLY. HEADER SEAL. WATER SENSOR ASSEMBLY. WATER SENSOR SCREW. SENSOR MOUNTING SEAL. CAP ASSEMBLY. HEATEfl

6. NUT. CAP 8. CAP, AIR BLEED

Fig. 43 PCV valve location-gasoline engines

REMOVAL & INSTALLATION > See Figures 44 and 45

Fig. 42 Exploded view of the fuel filter—6.5L engines

1. Remove the PCV valve from the cylinder head cover or trom the manifold-to-crankcase hose. 2. Visually inspect all hose connections and hoses for cracks, clogs or deterioration and replace as necessary.

1-16

GENERAL INFORMATION AND MAINTENANCE

87981POB

Fig. 44 Pull the PCV valve out of the cylinder head

Fig. 45 Disconnect the PCV valve from the hose and remove the valve from the vehicle

Crankcase Depression Regulator and Flow Control Valve SERVICING » See Figures 46 and 47 —This system is found only on diesel engines.

The Crankcase Depression Regulator (CDR) is designed to scavenge crankcase vapors in basically the same manner as the PCV valve on gas ine engines. The valve is located by the right cylinder head cover. On this sy! tern, the valve and filter are replaced as an assembly. The ventilation pipes and tubes should also be cleaned and replaced s wear and tear dictates. —Do not attempt to test the crankcase controls on these diesels. Instead, clean the valve cover filter assembly and vent pipes and heck the vent pipes. Replace the breather cap assembly every 30,000 i illes (48,000 km). Replace all rubber fittings as required every 15,000 miles (24.000 km).

HOSE

CDRVALVE

HEATSHIELD

TURBO CHARGER

Fig. 47 COR valve—6.5L engine

Evaporative Canister SERVICING The only regular maintenance that need be performed on the evaporatil/e emission canister is to regularly change the filter (on those 1988-90 motlels which utilize one; 1991-98 trucks do not have a canister filter) and check the condition of the hoses. If any hoses need replacement, use only hoses wr ich are marked EVAP. No other type should be used. Whenever the vapor ven hose is replaced, tne reslr/cfor adjacent to the canister should also be replaced

CDR V A L V E

HOSE

INTAKE MANIFOLD

RIGHT VALVE COVER 84901038

Fig. 46 COR valve—6.2L engine

The evaporative emission canister is located on the left side of the engine compartment, with a filter located in its bottom (if applicable). — For further information on the evaporative emission system, please refer to Section 4.

To service the canister filter: 1. Note the installed positions of the hoses, tagging them as necessary, in case any have to be removed. 2. Loosen the clamps and remove the canister. 3. Pull the filter out and throw it away. 4. Install a new canister filter. 5. Install the canister and tighten the clamps. 6. Check the hoses.

Battery PRECAUTIONS Always use caution when working on or near the battery. Never allow a tool to bridge the gap between the negative and positive battery terminals. Also, be careful not to allow a tool to provide a ground between the positive cable/terminal and any metal component on the vehicle. Either of these conditions will cause a short circuit, leading to sparks and possible personal injury. Do not smoke or all open flames/sparks near a battery; the gases contained in th.3 battery are very explosive and, if ignited, could cause severe injury or death. All batteries, regardless of type, should be carefully secured by a battery hold-down device. If not, the terminals or casing may crack from stress during vehicle operation. A battery which is not secured may allow acid to leak, making it discharge faster. The acid can also eat away at components under the hood. Always inspect the battery case for cracks, leakage and corrosion. A white corrosive substance on the battery case or on nearby components would indicate a leaking or cracked battery. If the battery is cracked, it should be replaced immediately. GENERAL MAINTENANCE Always keep the battery cables and terminals free of corrosion. Check and clean these components about once a year. Keep the top of the battery clean, as a film of dirt can help discharge a battery that is not used for long periods. A solution of baking soda and water may be used for cleaning, but be careful to flush this off with clear water. DO NOT let any of the solution into the filler holes. Baking soda neutralizes battery acid and will de-activate a battery eel I. Batteries in vehicles which are not operated on a regular basis can fall victim to parasitic loads (small current drains which are constantly drawing current from the battery). Normal parasitic loads may drain a battery on a vehicle that is in storage and not used for 6-8 weeks. Vehicles that have additional accessories such as a phone or an alarm system may discharge a battery sooner. If the vehicle is to be stored for longer periods in a secure area and the alarm system is not necessary, the negative battery cable should be disconnected to protect the battery. Remember that constantly deep cycling a battery (completely discharging and recharging it) will shorten battery lite.

GENERAL INFORMATION AND MAINTENANCE BATTERY FLUID

1-17

** CAUTION

I See Figure 48

Battery electrolyte contains sulfuric acid. If you should splash any on your skin or in your eyes, flush the affected area with plenty of clear water. If it lands in your eyes, get medical help immediately.

Check the battery electrolyte level at least once a month, or more often in hot weather or during periods of extended vehicle operation. On non-sealed batteries, the level can be checked either through the case (if translucent) or by removing the cell caps. The electrolyte level in each cell should be kept filled to the split ring inside each cell, or the line marked on the outside of the case. If the level is low, add only distilled water through the opening until the level is correct. Each cell must be checked and filled individually. Distilled water should be used, because the chemicals and minerals found in most drinking water are harmful to the battery and could significantly shorten its life. If water is added in freezing weather, the vehicle should be driven several miles to allow the water to mix with the electrolyte. Otherwise, the battery could freeze. Although some maintenance-free batteries have removable cell caps, the electrolyte condition and level on all sealed maintenance-free batteries must be checked using the built-in hydrometer "eye." The exact type of eye will vary. But, most battery manufacturers, apply a sticker to the battery itself explaining the readings. â&#x20AC;˘â&#x20AC;˘â&#x20AC;˘Although the readings trom built-in hydrometers will vary, a green eye usually indicates a properly charged battery with sufficient fluid level. A dark eye is normally an indicator of a battery with sufficient fluid, but which is low in charge. A light or yellow eye usually indicates that electrolyte has dropped below the necessary level. In this last case, sealed batteries with an insufficient electrolyte must usually be discarded.

The fluid (sulfuric acid solution) contained in the battery cells will tell you many things about the condition of the battery. Because the cell plates must be kept submerged below the fluid level in order to operate, the fluid level is extremely important. And, because the specific gravity of the acid is an indication of electrical charge, testing the fluid can be an aid in determining if the battery must be replaced. A battery in a vehicle with a properly operating charging system should require little maintenance, but careful, periodic inspection should reveal problems before they leave you stranded. At least once a year, check the specific gravity of the battery. It should be between 1.20 and 1.26 on the gravity scale. Most auto stores carry a variety of inexpensive battery hydrometers. These can be used on any non-sealed battery to test the specific gravity in each cell. The battery testing hydrometer has a squeeze bulb at one end and a nozzle at the other. Battery electrolyte is sucked into the hydrometer until the float is lifted from its seat. The specific gravity is then read by noting the position of the float. If gravity is low in one or more cells, the battery should be slowly charged and checked again to see if the gravity has come up. Generally, if after charging, the specific gravity between any two cells varies more than 50 points (0.50), the battery should be replaced, as it can no longer produce sufficient voltage to guarantee proper operation.

Checking the Specific Gravity

CABLES

I See Figures 49, 50 and 51 A hydrometer is required to check the specific gravity on all batteries that are not maintenance-free. On batteries that are maintenance-free, the specific gravity is checked by observing the built-in hydrometer "eye" on the top of the battery case.

TCCA1G02

Fig. 48 Maintenance-free batteries usually contain a built-in hydrometer to check fluid level

Fig. 49 On non-sealed batteries, the fluid level can be checked by removing the cell caps

I See Figures 52 thru 57 Once a year (or as necessary), the battery terminals and the cable clamps should be cleaned. Loosen the clamps and remove the cables, negative cable first. On top post batteries, the use of a puller specially made for this purpose is recommended. These are inexpensive and available in most parts stores. Side terminal battery cables are secured with a small bolt. Clean the cable clamps and the battery terminal with a wire brush, until all corrosion, grease, etc., is removed and the metal is shiny. It is especially important to clean the inside of the clamp thoroughly (an old knife is useful here), since a small deposit of oxidation there will prevent a sound connection and inhibit starting or charging. Special tools are available for cleaning these parts, one type for conventional top post batteries and another type for side terminal batteries. It is also a good idea to apply some dielectric grease to the terminal, as this will aid in the prevention of corrosion. After the clamps and terminals are clean, reinstall the cables, negative cable last; DO NOT hammer the clamps onto battery posts. Tighten the clamps securely, but do not distort them. Give the clamps and terminals a thin external coating of grease after installation, to retard corrosion. Check the cables at the same time that the terminals are cleaned. If the cable insulation is cracked or broken, or if the ends are frayed, the cable should be replaced with a new cable of the same length and gauge.

Fig. 50 If the fluid level is low, add only distilled water until the level is correct

Fig. 51 Check the specific gravity of the battery's electrolyte with a hydrometer

1-18

GENERAL INFORMATION AND MAINTENANCE

Fig. 54 A wire brush may be used to clean any corrosion or foreign material from the cable

Fig. 52 Loosen the battery cable retaining nut.

TCCA1P06

TCCA1P05

Fig. 55 The wire brush can also be used to remove any corrosion or dirt from the battery terminal

Fig. 56 Th battery terminal can also be

cleaned using a solution of baking soda and water

replace all drive belts at one time, as a preventive maintenance measure, during this service operation.

CHARGING

ADJUSTMENT

** CAUTION The chemical reaction which takes place in all batteries gene ates explosive hydrogen gas. A spark can cause the battery to expode and splash acid. To avoid personal injury, be sure there is pn ter ventilation and take appropriate fire safety precautions when vorking with or near a battery. A battery should be charged at a slow rate to keep the plates inside fr mgetting too hot. However, if some maintenance-free batteries are allowed to ischarge until they are almost "dead," they may have to be charged at a hi h rate to bring them back to "life." Always follow the charger manufacturer's in: ructions on charging the battery. REPLACEMENT When it becomes necessary to replace the battery, select one with an age rating equal to or greater than the battery originally installed. Deteric and just plain aging of the battery cables, starter motor, and associated v makes the battery's job harder in successive years. This makes it pruden install a new battery with a greater capacity than the ofd.

Fig. 57 Before connecting the cables, it's a good idea to coat the terminals with a small amount of dielectric grease

mperation res to

INSPECTION

V-Belts > See Figures 63 and 64 Belt tension should be checked with a gauge made for the purpose. If a tension gauge is not available, tension can be checked with moderate thumb pressure applied to the belt at its longest span midway between pulleys. If the belt has a free span less than 12 in. (305mm), it should deflect approximately Va-V* in. (3-6mm). If the span is longer than 12 in. (305mm), deflection can range between Vs in. (3mm) and % in. (9.5mm). If a tension gauge is available use the following procedure: 1. Place a belt tension gauge at the center of the greatest span of a warm, not hot, drive belt and measure the tension. 2. If the belt is not within the specification, loosen the component mounting bracket and adjust to specification. 3. Run the engine at idle for 15 minutes to allow the belt to reseat itself in the pulleys. 4. Allow the drive belt to cool and re-measure the tension. Adjust as necessary to meet the following specifications: « V6, V8 gasoline engines: used—90 ft. Ibs. (122Nm); new—135 ft. Ibs. (183 Nm). • 6—4.8L: used—90 ft. Ibs. (122 Nm); new—169 ft. Ibs. (229 Nm). • V8—6.2L76.5L diesel: used—67 ft. Ibs. (90 Nm); new—146 ft. Ibs. (197 Nm). •A belt is considered "used" after 15 minutes of operation.

I See Figures 58, 59, 60, 61 and 62

Serpentine Belts

Inspect the belts for signs of glazing or cracking. A glazed belt will be perfectly smooth from slippage, while a good belt will have a slight texture t fabric visible. Cracks will usually start at the inner edge of (he belt and run out ard. All worn or damaged drive belts should be replaced immediately. It is be to

The serpentine belt tension can be checked by simply observing the belt acceptable belt wear range indicator located on the tensioner spindle. If the belt does not meet the specified range, it must be replaced.

GENERAL INFORMATION AND MAINTENANCE 1-19

TCCS1215

Fig. 58 There are typically 3 types of accessory drive belts found on vehicles today

Fig. 59 An example of a healthy drive belt

Fig. 60 Deep cracks in this belt will cause flex, building up heat that will eventually lead to belt failure

Nippondenso Borroughs

t TCCS1216

Fig. 61 The cover of this belt is worn, exposing the critical reinforcing cords to excessive wear

Fig. 62 Installing too wide a belt can result in serious belt wear and/or breakage

Fig. 63 Common belt tension gauges

REMOVAL & INSTALLATION RULER

BELT DEFLECTION

V-Belts I See Figures 65, 66 and 67

STRAIGHT EDGE

MAKE SURE RULER IS PERPENDICULAR TO STRAIGHT EDGE

Fig. 64 Measuring belt deflection

Fig. 65 Push the component toward the engine and slip off the belt

1. Loosen the driven accessory's pivot and mounting bolts. Remove the belt. 2. Install the belt. Move the accessory toward or away from the engine until the tension is correct. You can use a wooden hammer handle, or broomstick, as a lever, but do not use anything metallic, such as a prybar. Certain models may utilize an adjusting bolt to do this work for you. Simply loosen the mounting bolt and turn the adjuster. 3. Tighten the bolts and recheck the tension. If new belts have been installed, run the engine for a few minutes, then recheck and readjust as necessary. It is better to have belts too loose than too tight, because overtight belts will lead to bearing failure, particularly in the water pump and alternator. However, loose belts place an extremely high impact load on the driven component due to the whipping action of the belt.

Fig. 66 Slip the new belt over tlie pulley

Fig. 67 Pull outward on the component and tighten the adjusting and mounting bolts

1-20 GENERAL INFORMATION AND MAINTENANCE Serpentine Belts » See Figure 68 1. On all models except the 7.4L engine with an Air Injector P or (AIR) pump (California emissions only), use a 1/2 in. breaker ba •:.itl' a socket placed on the tensioner pulley bolt, rotate the tensioner to reli ve belt tension. 2. On all 7.4L engines with an AIR pump (California emissions only , use a suitable wrench on the pulley axis bolt to rotate the tensioner clockwise relieve belt tension. 3. Remove the serpentine belt. To install: 4. Route the belt over all the pulleys except the tensioner. 5. On all models except the 7.4L engine with an AIR pump (Califorr a emissions only), place the breaker bar and socket on the tensioner pulley bo! and rotate the tensioner to the released position. 6. Install the belt and return the pulley to its original position. 7. On all 7.4L engines with an AIR pump (California emissions only use a suitable wrench on the pulley axis bolt to rotate the tensioner clockwise o relieve belt tension. 8. Install the belt and return the pulley to its original position. 9. Check that the belt is properly seated in each pulley.

Fig. 68 Rotate the tensioner with a breaker bar to relieve belt t nsion

Fig. 70 Drive belt routing—1988-90 5.7L and 6.2L engines

Fig. 71 Drive belt routing—1988-90 4.3L, 5.0L and 7.4L engines

BELT ROUTING I See Figures 69 thru 88

A. R/V3 5 7L (W/O A'C) B. C. D. 50

R.V35 7L (W A;C} R/V1.2 5.7L (W AC) R'Vl.a 5 7L (W/O A/C) Coolanl Pump Pulley

51. Crankstial Pulley 52 Generator Pultey 54. Power Steering Pump Pulley 50

Waler pump pulle

Fig. 69 Drive belt routing—1988-90 5.7L HD engines

55 Aif Conditioning Compressor Pulley 56 Idler Pulley 60. Tensioner

Fig. 72 Drive belt routing—1991 5.7L engines, R/V series

GENERAL INFORMATION AND MAINTENANCE 1-21

A. B. 50. 51. 52. 54. 55.

R/V 6.2L <w A/C) R/V 6.2L (w/o A/C) Coolant Pump Pulley Crankshaft Pulley Generator Pulley Power Steering Pump Pulley Air Conditioning Compressor Pulley

Fig. 73 Drive belt routing—1991 6.2L engines, R/V series

A. B. C. 50. 5! 52 54 55 56.

P3 6.26 HD (W P/S, P/B Pump) P3 4.3L, 5.7L (W P/S) P3 5.7L (W P.'S and A'C) Coolant Pump Pulley Crankshaft Pulley Generator Pulley Power Steering Pump Pulley Air Conditioning Compressor Pulley Idler Pulley

Fig. 74 Drive belt routing—1991 6.2L HD and 4.3L engines

1 (W A/C) L (W/O A/C)

it Pump Pulley ower Steering Pump P ir Conditioning Compre Her Pulley

Fig. 75 Drive belt routing—1991 7.4L engines, R/V series

1. 2. 34. 5. 6. 7. 8. 9.

Belt Air Conditioning Compressor Tensioner Generator Power Steering Pump Crankshaft Coolant Pump AIR Pump Idler Pulley

* 4.31, 5.0L, 5.7L Engines A. With Power Steering Pump B- With Power Steering Pump and A/C Compressor C. With Power Steering Pump and AIR Pump D. With Power Steering Pump and AIR Pump and A/C Compressor * 6.2L Diesel Engines E. With Air Conditioning F. With Air Conditioning or Vacuum Pump or Idler Pulley

Fig. 76 Drive belt routing—1991 4.3L, 5,01, 5.7L and 6.2L engines, C/K series

A. 7.4L Engine without Air Conditioning B. 7.4L Engine with Air Conditioning 2. Air Conditioning Compressor 3. Tensioner

4 5. 6. 7. 8. 9.

Generator Power Steering Pump Crankshaft Water Pump AIR Pump Idler Pulley

Fig. 77 Drive belt routing—1991 7.4L engines, C/K series

1-22

A B C D E F H

GENERAL INFORMATION AND MAINTENANCE

A/C compressor pulley Drive belttensioner pulley Generator pulley Power steering pump pulley Crankshaft pulley Coolanl pump pulley Idler pulley

WITH A|I ;

A BC D E F. H.

PULLEY. A/C COMPRESSOR PULLEY. DRIVE BELT TENSIONEH PULLEY, GENERATOR PULLEY, POWER STEERING PUMP PULLEY, CRANKSHAFT PULLEY. COOLANT PUMP PULLEY, IDLER

E4901065

Fig. 78 Drive belt routing—1992-93 4.3L, 5.0L and 5.7L engines without AC

A B C D E

A/C compressor pulley Drive belttensiorier pulley Generator pulley Power steering pump pull Crankshaft pulley

A PULLEY, A/C COMPRESSOR B PULLEY, DRIVE BELT TENSIONER C. PULLEY. GENERATOR D PULLEY, POWER STEERING E PULLEY CRANKSHAFT F PULLEY, COOLANT PUMP H PULLEY. IDLER I PULLEY. A I R. PUMP

H Idler pulley I A I R pump pulley

Fig. 79 Drive belt routing—1992-93 4.3L and 5.7L engines with AC

PULLEY. AC COMPRESSOR PULLEY, DRIVE 8ELT TENSONEH PULLEY. GENERATOR PULLEY. POWER STEERING PUMP

WITHOUT A/C

Fig. 83 Drive belt routing—1994-95 4.3L, 5.0L and 5.7L engines, C/K series (with AIR)

C1 WITH A/C

C1 WITH A/C A. B C 0

Fig. 82 Drive belt routing—1994-95 4.3L, 5.0L and 5.7L engines, C/K series (without AIR)

CK 2,3 WITHOUT A/C E. F H. t.

CK 2,3 WITHOUT A/C

CK 2,3 WITH

PULLEY. CRANKSHAFT PULLEY, COOLANT PUMP PULLEY. IDLER PULLEY, A.J.R. PUMP

Fig. 80 Drive belt routing—1992-93 7.4L engines

A PULLEY. A/C COMPRESSOR 8. ULLEY, DRIVE BEIT TENSIONEH C ULLEY. GENERATOR O ULLEY, POWER STEERING PUMF E ULLEY, CRANKSHAFT F PULLEY. COOLANT PUMP G. ULLEY. VACUUM PUMP H. ULLEY. IDLER

Fig. 81 Drive belt routing—1992-93 6.2L and 6.5L engines

A PULLEY. A/C COMPRESSOR 8 PULLEY. DRIVE BELT TENSIONEH C PULLEY. GENERATOR 0 PULLEY. POWER STEERING PUMP

E F M i

PULLEY. PULLEY, PULLEY, PULLEY,

CK 2,3 WITH A/C

CRANKSHAFT COOLANT PUMP IDLER A.I.R PUMP

Fig. 84 Drive belt routing—1994-95 7.4L engines, C1. C/K 2, 3 series

V. A/C COMPRESSOR V DRIVE BELT TENSIONEH V, GENERATOR Y, POWER STEERING PUMI E. ULLEY. CRANKSHAFT f PULLEY, COOLANT PUMP Y. VACUUM PUMP ULLEY, IDLER

Fig. 85 Drive belt routing—1994-95 diesel engines

GENERAL INFORMATION AND MAINTENANCE 1-23 Hoses

^GENERATOR PULLEY

GENERATOR PULLEY

INSPECTION

IDLER PULLEY COMPRESSOR PULLEY

» See Figures 89, 90, 91 and 92

WATER PUMP PULLEY

C/SHAFT PULLEY

C/SHAFT PULLEY-'

Fig. 86 Drive belt routing—1996-98 4.3L, 5.0L and 5.7L engines

Upper and lower radiator hoses along with the heater hoses should be checked for deterioration, leaks and loose hose clamps at least every 15,000 miles (24,000 km). It is also wise to check the hoses periodically in early spring and at the beginning of the fall or winter when you are performing other maintenance. A quick visual inspection could discover a weakened hose which might have left you stranded if it had remained unrepaired. Whenever you are checking the hoses, make sure the engine and cooling system are cold. Visually inspect for cracking, rotting or collapsed hoses, and replace as necessary. Run your hand along the length of the hose. If a weak or swollen spot is noted when squeezing the hose wall, the hose should be replaced.

A/C COMPRESSOR PULLEY 7.4 L ENGINE WITHOUT K19

. ,••:, jj IDLER PULLEY

TCCS121S

Fig. 89 The cracks developing along this hose are a result of agerelated hardening REMOVAL & INSTALLATION TENSIONER PULLEY

» See Figures 93, 94, 95 and 96 1. Remove the radiator pressure cap.

** CAUTION

A.I.R. PUMP PULLEY

WITHOUT A/C

Fig. 87 Drive belt routing—1996-98 7.4L engines C/K series

- Av'C COMPRESSOR ^ IDLER PULLEY (IF NOT EQUIPPED WITH A/C)

A/C COMPRESSOR IDLER PULLEY GENERATOR

Never remove the pressure cap while the engine is running, or personal injury from scalding hot coolant or steam may result. If possible, wait until the engine has cooled to remove the pressure cap. If this is not possible, wrap a thick cloth around the pressure cap and turn it slowly to the stop. Step back while the pressure is released from the cooling system. When you are sure all the pressure has been released, use the cloth to turn and remove the cap. 2. Position a clean container under the radiator and/or engine draincock or plug, then open the drain and allow the cooling system to drain to an appropriate level. For some upper hoses, only a little coolant must be drained. To remove hoses positioned lower on the engine, such as a lower radiator hose, the entire cooling system must be emptied.

** CAUTION When draining coolant, keep in mind that cats and dogs are attracted by ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain coolant into a scalable container. Coolant may be reused unless it is contaminated or several years old.

C'SHAFT ~f WITHOUT SECOND GENERATOR

C/SHAFT WITH SECOND GENERATOR

Fig. 88 Drive belt routing—1996-98 diesel engines

3. Loosen the hose clamps at each end of the hose requiring replacement Clamps are usually either of the spring tension type (which require pliers to squeeze the tabs and loosen) or of the screw tension type (which require screw or hex drivers to loosen). Pull the clamps back on the hose away from the connection.

1-24 GENERAL INFORMATION AND MAINTENANCE

Fig. 90 A hose clamp that is too tight can cause older hoses to separate and tear on either side of the clamp

Fig. 91 A siift spongy hose (identifiable by the swollen section) will eventually burst and should be replaced

Fig. 92 Hoses are likely to deteriorate from the inside if the cooling system is not periodically flushed

Approximately 1/4 inch

ose requiring replacement and Fig. 93 Remove the radiator cap

Fig. 95 Position the hose clamp so that it is about 1/4 in. from the end of the hose

To install: 6. Dip the ends of the new hose into clean engine coolant to ease installation. 7. Slide the clamps over the replacement hose, then slide the hose ends over the connections into position. Position and secure the clamps at least 1A in. (6.35mm) from the ends of the hose. Make sure they are located beyond the raised bead of the connector. 9. Close the radiator or engine drains and properly refill the cooling system with the clean drained engine coolant or a suitable mixture of ethylene glycol coolant and water. 10. If available, install a pressure tester and check for leaks. If a pres-sure tester is not available, run the engine until normal operating temperature is reached (allowing the system to naturally pressurize), then check for leaks.

** CAUTION

Fig. 96 Properly refill the cooling system with a suitable mixture ethylene glycol coolant and water 4. Twist, pull and slide the hose off the fitting, taking care not to darjjage the neck of the component from which the hose is being removed. â&#x20AC;˘Âťlt the hose is stuck at the connection, do not try to insert a screw triver or other sharp tool under the hose end in an effort to free it, as the connection and/or hose may become damaged. Heater connections especially may be easily damaged by such a procedure. If the hose is ti: be replaced, use a single-edged razor blade to make a slice along the portion of the hose which is stuck on the connection, perpendicular to he end of the hose. Do not cut deep so as to prevent damaging the coi nection. The hose can then be peeled from the connection and discarded. 5. Clean both hose mounting connections. Inspect the condition of I IB hose clamps and replace (hem, if necessary.

If you are checking for leaks with the system at normal operating temperature, BE EXTREMELY CAREFUL not to touch any moving or hot engine parts. Once temperature has been reached, shut the engine OFF, and check for leaks around the hose fittings and connections which were removed earlier.

CV-Boots INSPECTION I See Figures 97 and 98 The CV (Constant Velocity) boots should be checked for damage each time the oil is changed and any other time the vehicle is raised for service. These boots keep water, grime, dirt and other damaging matter from entering the CV-joints. Any of these could cause early CV-joint failure which can be expensive to repair. Heavy grease thrown around the inside of the front wheel(s) and on the brake caliper/drum can be an indication of a torn boot.

GENERAL INFORMATION AND MAINTENANCE 1-25 Thoroughly check the boots for missing clamps and tears. If the boot is damaged, it should be replaced immediately. Please refer to Section 7 for procedures.

Spark Plugs I See Figure 99

A typical spark plug consists of a metal shell surrounding a ceramic insulator. A metal electrode extends downward through the center of the insulator and protrudes a small distance. Located at the end of the plug and attached to the side of the outer metal shell is the side electrode. The side electrode bends in at a 90Â° angle so that its tip is just past and parallel to the tip of the center electrode. The distance between these two electrodes (measured in thousandths of an inch or hundredths of a millimeter) is called the spark plug gap. The spark plug does not produce a spark but instead provides a gap across which the current can arc. The coil produces anywhere from 20,000 to 50,000 volts (depending on the type and application) which travels through the wires to the spark plugs. The current passes along the center electrode and jumps the gap to the side electrode, and in doing so, ignites the air/fuel mixture in the combustion chamber. SPARK PLUG HEAT RANGE I See Figure 100

Spark plug heat range is the ability of the plug to dissipate heat. The longer the insulator (or the farther it extends into the engine), the hotter the plug will operate; the shorter the insulator (the closer the electrode is to the block's cooling passages) the cooler it will operate. A plug that absorbs little heat and remains too cool will quickly accumulate deposits of oil and carbon since it is not hot enough to burn them off. This leads to plug fouling and consequently to misfiring. A plug that absorbs too much heat will have no deposits but, due to the excessive heat, the electrodes will burn away quickly and might possibly

km). As the gap increases, the plug's voltage requirement also increases. It requires a greater voltage to jump the wider gap and about two to three times as much voltage to fire the plug at high speeds than at idle. The improved air/fuel ratio control of modern fuel injection combined with the higher voltage output of modern ignition systems will often allow an engine to run significantly longer on a set of standard spark plugs, but keep in mind that efficiency will drop as the gap widens (along with fuel economy and power). When you're removing spark plugs, work on one at a time. Don't start by removing the plug wires all at once, because, unless you number them, they may become mixed up. Take a minute before you begin and number the wires with tape. 1. Disconnect the negative battery cable, and if the vehicle has been run recently, allow the engine to thoroughly cool. 2. Carefully twist the spark plug wire boot to loosen it, then pull upward and remove the boot from the plug. Be sure to pull on the boot and not on the wire, otherwise the connector located inside the boot may become separated. 3. Using compressed air, blow any water or debris from the spark plug well to assure that no harmful contaminants are allowed to enter the combustion chamber when the spark plug is removed. If compressed air is not available, use a rag or a brush to clean the area. -Remove the spark plugs when the engine is cold, if possible, to prevent damage to the threads. If removal of the plugs is difficult, apply a few drops of penetrating oil or silicone spray to the area around the base of the plug, and allow it a few minutes to work. 4. Using a spark plug socket that is equipped with a rubber insert to properly hold the plug, turn the spark plug counterclockwise to loosen and remove the spark plug from the bore.

** WARNING Be sure not to use a flexible extension on the socket. Use of a flexible extension may allow a shear force to be applied to the plug. A shear force could break the plug off in the cylinder head, leading to costly and frustrating repairs.

PORCELAIN INSULATOR INSULATOR CRACKS OFTEN OCCUR HERE

ADJUST FOR PROPER GAP SIDE ELECTRODE (BEND TO ADJUST GAP) TCCS1010

Fig. 97 CV-boots must be inspected periodically for damage

TCCS1045

Fig. 98 A torn boot should be replaced immediately

lead to preignition or other ignition problems. Preignition takes place when plug tips get so hot that they glow sufficiently to ignite the air/fuel mixture before the actual spark occurs. This early ignition will usually cause a pinging during low speeds and heavy loads. The general rule of thumb for choosing the correct heat range when picking a spark plug is: if most of your driving is long distance, high speed travel, use a colder plug; if most of your driving is stop and go, use a hotter plug. Original equipment plugs are generally a good compromise between the 2 styles and most people never have the need to change their plugs from the factory-recommended heat range. REMOVAL & INSTALLATION A set of spark plugs usually requires replacement after about 20,000-30,000 miles (32,000-48,000 km), depending on your style of driving. In normal operation plug gap increases about 0.001 in. (0.025mm) for every 2500 miles (4000

CENTER ELECTRODE: FILE FLAT WHEN ADJUSTING GAP, DO NOT BEND

Fig. 99 Cross-section of a spark plug

THE SHORTER THE PATH THE FASTER THE HEAT IS DISSIPATED AND THE COOLER HE PLUG

HEAVY LOADS. HIGH SPEEDS SHORT Insulator T,p f a s t Heat Tianster L O W E R Heat Range COLD PLUG

Fig. 100 Spark plug heat range

THE LONGER THE PATH. THE SLOWER THE HEAT is DISSIPATED AND THE HOTTER Hâ&#x201A;Ź PLUG

SHORT TRIP STOP-AND-GO LONG Insulalor Tip Slow Heat Transfer HIGHER Heal Range HOT PL'UG

1-26 GENERAL INFORMATION AND MAINTENANCE To install: 5. Inspect the spark plug boot for tears or damage. If a damaged boct is found, the spark plug wire must be replaced. 6. Using a wire feeler gauge, check and adjust the spark plug gap. When jsing a gauge, the proper size should pass between the electrodes with a slight drag. The next larger size should not be able to pass while the next smaller size should pass freely. 7. Carefully thread the plug into the bore by hand. If resistance is felt before the plug is almost completely threaded, back the plug out and begin threading again. In small, hard to reach areas, an old spark plug wire and boot could be used a|s a threading tool. The boot will hold the plug while you twist the end of the wife and the wire is supple enough to twist before it would allow the plug to crossthread.

8. Carefully tighten the spark plug. If the plug you are installing is equipped with a crush washer, seat the plug, then tighten about Vi turn to crush the washer. If you are installing a tapered seat plug, tighten the plug to specifications provided by the vehicle or plug manufacturer. 9. Apply a small amount of silicone dielectric compound to the end of the spark plug lead or inside the spark plug boot to prevent sticking, then install the boot to the spark plug and push until it clicks into place. The click may be felt or heard, then gently pull back on the boot to assure proper contact. INSPECTION & GAPPING Âť See Figures 101,102,103,104 and 105

> WARNING

Do not use the spark plug socket to thread the plugs. Always carefully thread the plug by hand or using an old plug wire to prevf nt the possibility of crossthreading and damaging the cylinder head ore.

Check the plugs for deposits and wear. If they are not going to be replaced, clean the plugs thoroughly. Remember that any kind of deposit will decrease the efficiency of the plug. Plugs can be cleaned on a spark plug cleaning machine, which can sometimes be found in service stations, or you can do an acceptable

A n o r m a l l y Âť orn s p a r k p l u g s ou Id h a v e l i g h t t a or g r a y d e p o s i t on the firing tip.

A carbon fouled plug, identified by sort, sooty, black deposits, may indicate an improperly tuned vehicle. Check the air cleaner, ignition components and engine control system .

This spark p been left in e n g i n e too I e v i d e n c e d by extreme gapwith such an gap can caus f i r i n g and st accompanied n o t i c e a b l e la power.

An oil fouled spark plug i n d i c a t e s an engine with worn poston rings and/or bad valve seals allowing excessive oil to enter the chamber.

ug has he ng, as the Plugs extreme m ismbl ing by a k of

A p h y s i c a l l y damaged s p a r k lug may b e e v i d e n c e if s e v e r e d e t o n ati o n in that cylinder Watch that cylindei ca refully betwee serv i c e s , as a c o n t i n u e d d e t o n a t i n wi.ll not o n l y darr age t h e plug, but co Id a l s o d a m a g e t h e ng i n e .

Fig. 101 Inspect the spark plug to determine engine running co ditions

A b r i d g e d or a l m o s t bridged spark plug, i d e n t i f i e d by a b u i l d up between the electrodes caused by excessive carbon or oil build-up on the plug.

GENERAL INFORMATION AND MAINTENANCE

1-27

& :

Fig. 102 A variety of tools and gauges are needed for spark plug service

Fig. 103 Checking the spark plug gap with a feeler gauge

job of cleaning with a stiff brush. If the plugs are cleaned, the electrodes must be filed flat. Use an ignition points file, not an emery board or the like, which will leave deposits. The electrodes must be filed perfectly flat with sharp edges; rounded edges reduce the spark plug voltage by as much as 50%. Check spark plug gap before installation. The ground electrode (the Lshaped one connected to the body of the plug) must be parallel to the center electrode and the specified size wire gauge (please refer to the Tune-Up Specifications chart for details) must pass between the electrodes with a slight drag. ••NEVER adjust the gap on a used platinum type spark plug. Always check the gap on new plugs as they are not always set correctly at the factory. Do not use a flat feeler gauge when measuring the gap on a used plug, because the reading may be inaccurate. A round-wire type gapping tool is the best way to check the gap. The correct gauge should pass through the electrode gap with a slight drag. If you're in doubt, try one size smaller and one larger. The smaller gauge should go through easily, while the larger one shouldn't go through at all. Wire gapping tools usually have a bending tool attached. Use that to adjust the side electrode until the proper distance is obtained. Absolutely never attempt to bend the center electrode. Also, be careful not to bend the side electrode too far or too often as it may weaken and break off within the engine, requiring removal of the cylinder head to retrieve it.

Fig. 104 Adjusting the spark plug gap

To check resistance: 1. Remove the distributor cap, leaving the wires in place. 2. Connect one lead of an ohmmeter to an electrode within the cap. 3. Connect the other lead to the corresponding spark plug terminal (remove it from the spark plug for this test). 4. Replace any wire which shows a resistance over 30,000 ohms. Generally speaking, however, resistance should not be over 25,000 ohms, and 30,000 ohms must be considered the outer limit of acceptability. It should be remembered that resistance is also a function of length. The longer the wire, the greater the resistance. Thus, if the wires on your truck are longer than the factory originals, the resistance will be higher, possibly outside these limits. REMOVAL & INSTALLATION When installing new wires, replace them one at a time to avoid mixups. Start by replacing the longest one first. 1. Remove the spark plug wire by gripping the boot firmly and disengaging the wire from the spark plug and the distributor. 2. Install the boot of the new wire firmly over the spark plug. Route the wire over the same path as the original.

Distributor Cap and Rotor

Spark Plug Wires

REMOVAL & INSTALLATION TESTING Carbureted Engines

> See Figures 106 and 107 At every tune-up/inspection, visually check the spark plug cables for burns cuts, or breaks in the insulation. Check the boots and the nipples on the distributor cap and/or coil. Replace any damaged wiring. Every 50,000 miles (80,000 Km) or 60 months, the resistance ot the wires should be checked with an ohmmeter. Wires with excessive resistance will cause misfiring, and may make the engine difficult to start in damp weather.

> See Figures 108,109,110 and 111 1. Remove the feed and module wire terminal connectors from the distributor cap. 2. Remove the retainer and spark plug wires from the cap. 3. Depress and release the 4 distributor cap-to-housing retainers and lift off the cap assembly.

o.on

Fig. 105 If the standard plug is in good condition, the electrode may be filed flat—WARNING: do not file platinum plugs

Fig. 106 Checking plug wire resistance through the distributor cap with an ohmmeter

TCCS1009

Fig. 107 Checking individual plug wire resistance with a digital ohmmeter

1-28

GENERAL INFORMATION AND MAINTENANCE

Fig. 108 Loosen the distributor hold-down fasteners

Fig. 109 II necessary, label and remove the spark plug wires from the distributor cap

Fig. 111 . . . then the rotor from the distributor 4. Remove the 4 coil cover screws and cover. 5. Using a finger or a blunt drift, push the spade terminals up out o tributor cap. 6 Remove all 4 coil screws and lift the coil, coil spring and rubber washer out of the cap coil cavity. 7. Remove the two rotor attaching screws (if equipped) and rotor. 8. Using a new distributor cap and rotor, reverse the above procedu assemble, being sure to clean and lubricate the rubber seal washer with trie lubricant.

the dis,eal esto dielec-

Fuel Injected Engines 1. 2. 3. 4.

Tag and remove the spark plug wires. Loosen the cap retaining fasteners and remove the cap. Remove the rotor from the distributor shaft. Installation is the reverse of removal.

INSPECTION 1. Remove the distributor cap and rotor as described in this sectior 2. Check the cap for wear, electrode cracks or damage. Replace if di fective. 3. Check the rotor for cracks and wear. Replace if defective.

Ignition Timing GENERAL INFORMATION ••This procedure does not apply to diesel engines. Ignition timing is the measurement, in degrees of crankshaft rotation of the point at which the spark plugs fire in each of the cylinders. It is measured in degrees before or after Top Dead Center (TDC) of the compression strok Ignition timing is controlled by turning the distributor in the engine.

8/981P14

Fig. 110 Remove the distributor cap . . .

Ideally, the air/fuel mixture in the cylinder will be ignited by the spark plug just as the piston passes TDC of the compression stroke. If this happens, this piston will be beginning the power stroke just as the compressed and ignited air/fuel mixture starts to expand. The expansion of the air/fuel mixture then forces the piston down on the power stroke and turns the crankshaft. Because it takes a fraction of a second for the spark plug to ignite the gases in the cylinder, the spark plug must fire a little before the piston reaches TDC. Otherwise, the mixture will not be completely ignited as the piston passes TDC and the full benefit of the explosion will not be used by the engine. The timing measurement is given in degrees of crankshaft rotation before the piston reaches TDC (BTDC). If the setting for the ignition timing is 5 degrees BTDC, the spark plug must fire 5 degrees before that piston reaches TDC. This only holds true, however, when the engine is at idle speed. As the engine speed increases, the pistons go faster. The spark plugs have to ignite the fuel even sooner if it is to be completely ignited when the piston reaches TDC. To do this, the distributor has a means to advance the timing of the spark as the engine speed increases. If the ignition is set too far advanced (BTDC), the ignition and expansion of the fuel in the cylinder will occur too soon and tend to force the piston down while it is stili traveling up. This causes engine ping. If the engine is too far retarded after TDC (ATDC), the piston will have already passed TDC and started on its way down when the fuel is ignited. This will cause the piston to be forced down for only a portion of its travel. This will result in poor engine performance and lack of power. Timing should be checked at each tune-up and any time the points are adjusted or replaced. It isn't likely to change much with HEI. The timing marks consist of a notch on the rim of the crankshaft pulley or vibration damper and a graduated scale attached to the engine front (timing) cover. A stroboscopic flash (dynamic) timing light must be used, as a static light is too inaccurate for emission controlled engines. There are three basic types of timing lights available. The first is a simple neon bulb with two wire connections. One wire connects to the spark plug terminal and the other plugs into the end of the spark plug wire for the No. 1 cylinder, thus connecting the light in series with the spark plug. This type of light is pretty dim and must be held very closely to the timing marks to be seen. Sometimes a dark corner has to be sought out to see the flash at all. This type of light is very inexpensive. The second type operates from the vehicle battery—two alligator clips connect to the battery terminals, while an adapter enables a third clip to be connected between No. 1 spark plug and wire. This type is a bit more expensive, but it provides a nice bright flash that you can see even in bright sunlight. It is the type most often seen in professional shops. The third type replaces the battery power source with 115 volt current. Some timing lights have other features built into them, such as dwell meters, or tachometers. These are convenient, in that they reduce the tangle of wires under the hood when you're working, but may duplicate the functions of tools you already have. One worthwhile feature, which is becoming more of a necessity with higher voltage ignition systems, is an inductive pickup. The inductive pickup clamps around the No. 1 spark plug wire, sensing the surges of high voltage electricity as they are sent to the plug. The advantage is that no mechanical connection is inserted between the wire and the plug, which eliminates false signals to the timing light. A timing light with an inductive pickup should be used on HEI systems.

GENERAL INFORMATION AND MAINTENANCE 1-29 CHECKINGS ADJUSTMENT

7. Turn the ignition OFF, remove the timing light and engage the "set timing" connector.

HEI Systems

1996-98 MODELS

1. Start the engine and allow it to reach operating temperature. Stop the engine and connect the timing light to the No. 1 (left front) spark plug wire, at the plug or at the distributor cap. You can also use the No. 6 wire, if it is more convenient. Numbering is illustrated in this section.

—The distributor on the 4.3L engine is non-adjustable and any attempt to adjust the distributor could cause cross firing. This procedure applies to the 5.0L, 5.7L and 7.4L engines.

«»Do not pierce the plug wire insulation with HEI; it will cause a miss. The best method is an inductive pickup timing light. 2. Clean off the timing marks and mark the pulley or damper notch and timing scale with white chalk. 3. Disconnect and plug the vacuum line at the distributor on models with a carburetor. This is done to prevent any distributor vacuum advance. On fuel injected models, disengage the timing connector which comes out of the harness conduit next to the distributor, this will put the system in the bypass mode. Check the underhood emission sticker for any other hoses or wires which may need to be disconnected. 4. Start the engine and adjust the idle speed to that specified on the Underhood Emissions label. With automatic transmission, set the specified idle speed in Park. It will be too high, since it is normally (in most cases) adjusted in Drive. You can disconnect the idle solenoid, if any, to get the speed down. Otherwise, adjust the idle speed screw. The tachometer connects to the TACH terminal on the distributor and to a ground on models with a carburetor. On models with fuel injection, the tachometer connects to the TACH terminal on the ignition coil. Some tachometers must connect to the TACH terminal and to the positive battery terminal. Some tachometers won't work with HEI.

WARNING Never ground the HEI TACH terminal; serious system damage will result.

The ignition timing is preset and cannot be adjusted. If the distributor position is moved, crossfiring may be induced. To check distributor position the following: •»An OBD-II compliant scan tool is required for this procedure 1. With the ignition OFF install scan tool to the Data Link Connector (DLC). 2. Start the engine and bring the vehicle to operating temperature. 3. Monitor cam retard on the scan tool. 4. If cam retard is between -2 and +2, the distributor is properly adjusted. 5. If cam retard is not between -2 and +2, the distributor must adjusted. 6. With the engine OFF loosen the distributor hold-down bolt. 7. Start the engine and check the cam retard reading. Rotate the distributor counterclockwise to compensate for a negative reading and clockwise to compensate for a positive reading. 8. Momentarily raise the engine speed to over 1000 RPM and check the cam retard reading. 9. If the proper reading is not achieved repeat Steps 7 and 8. 10. When the proper reading has been achieved, tighten the distributor hold-down bolt and disconnect the scan tool.

Valve Lash All engines described in this book use hydraulic lifters, which reguire no periodic adjustment. In the event of cylinder head removal or any operation that requires disturbing the rocker arms, the rocker arms will have to be adjusted.

5. Aim the timing light at the pointer marks. Be careful not to touch the fan, because it may appear to be standing still. If the pulley or damper notch isn't aligned with the proper timing mark (see the Underhood Emissions label), the timing will have to be adjusted.

ADJUSTMENT

•»TDC or Top Dead Center corresponds to OB, or BTDC, or Before Top Dead Center may be shown as BEFORE. A, or ATDC, or After Top Dead Center may be shown as AFTER.

1. Remove the rocker arm cover. 2. Mark the distributor housing at the No. 1 and No. 6 wire positions and remove the cap. 3. Turn the crankshaft until the rotor points to the No. 1 position. The following valves can be adjusted: • No. 1 exhaust and intake • No. 2 intake • No. 3 exhaust • No. 4 intake • No. 5 exhaust To adjust a valve, back off the adjusting nut until lash (play) is felt at the pushrod. Tighten the nut just until all lash is removed. This can be determined by rotating the pushrod with your fingers. When all lash is removed, the pushrod wil! stop rotating. When all play is removed, tighten the nut 1 full turn (360°). 4. Rotate the crankshaft until the rotor points to the No. 6 position. The following valves can be adjusted: • No. 2 exhaust • No. 3 intake • No. 4 exhaust • No. 5 intake • No. 6 intake and exhaust 5. Install the distributor cap, 6. Install the rocker cover.

6. Loosen the distributor base clamp locknut. You can buy trick wrenches which make this task a lot easier. 7. Turn the distributor slowly to adjust the timing, holding it by the body and not the cap. Turn the distributor in the direction of rotor rotation to retard, and against the direction of rotation to advance. 8. Tighten the locknut. Check the timing again, in case the distributor moved slightly as you tightened it. 9. Reinstall the distributor vacuum line or the timing connector. Correct the idle speed. 10. Stop the engine and disconnect the timing light. Distributor ignition (Dl) Systems 1995 MODELS

"••Refer to the underhood label for the proper timing setting. 1. Engage the parking brake, block the wheels and set the transmission in P. 2. Disconnect the Ignition Control (1C) system by disengaging the "set timing connector". This is a single wire sealed connector that has a tan with black stripe lead. This wire comes out of the wiring harness below the heater case. 3. With the ignition switch OFF, connect the timing light pickup lead to the No. 1 spark plug wire. 4. Start the engine and point the timing light at the timing mark on the balancer or pulley and check the timing. 5. If the timing is not within specifications refer to the underhood emission sticker, loosen the distributor hold-down bolt. Slowly rotate the distributor until the proper timing setting is achieved. 6. Tighten the hold-down bolt and recheck the timing.

4.8L Engines

V6 and V8 Engines » See Figure 112 Valve adjustment on 1991-98 7.4L engines and 1995-98 models equipped with V6 engines is not required. These models use a positive stop shoulder. On models with a positive stop shoulder, simply tighten the rocker arm retainers to the torque listed in the torque specifications chart in this section.

1-30 GENERAL INFORMATION AND MAINTENANCE On models not equipped with positive stop shoulders, perform the sleps outlined in this procedure. 1. Remove the rocker covers and gaskets. 2. Crank the engine until the mark on the damper aligns with the TDC or 0 mark on the timing tab and the engine is in No. 1 firing position. Tils can be determined by placing your finger on the No. 1 cylinder valves as the marks align. If the valves do not move, it is in No. 1 firing position. If the valves move, it is in No. 6 firing position (No. 4 on the V6) and the crankshaft should be rotated 1 more revolution to the No. 1 firing positions To adjust a valve, back off the adjusting nut until lash (play) is felt at thti pushrod. Tighten the nut just until all lash is removed. This can be dietermined by rotating the pushrod with your fingers. When all lash is removed, the pushrod will stop rotating. When all play is removed, tighten the iuM

Idle Speed and Mixture Adjustments CARBURETED ENGINES Mixture screws are concealed under staked-in plugs. Idle mixture is adjustable only during carburetor overhaul, and requires the addition of propane as an artificial mixture enricher. For these reasons, mixture adjustments are not considered part of routine maintenance. Refer to Section 5 for these procedures. 4.8L Engines CURB IDLE SPEED

With the engine in No. 1 firing position, the following valves can adjusted: V6 Engines • Exhaust—1,5, • Intake—1,2, 3 V8 Engines • Exhaust—1,3,4,8 • Intake—1,2,5,7 Crank the engine 1 full revolution until the marks are again in ah nment. This is No. 6 firing position (No. 4 on the V6). The following valves cannow be adjusted: V6 Engines • Exhaust—2, 3, 4 • Intake—4,5, 6 V8 Engines • Exhaust—2,5,6,7 • Intake—3,4, 6. 5. Reinstall the rocker arm covers using new gaskets. 6. Install the distributor cap and wire assembly.

I See Figure 113 With the idle speed solenoid energized, turn the solenoid body to establish the curb idle speed shown on your underhood sticker. BASE IDLE SPEED With the solenoid wire disconnected, turn the V& in. hex head solenoid plunger adjusting screw to establish the base idle speed shown on your underhood sticker. 5.7L Engines I See Figures 114 and 115 1. All adjustments should be made with the engine at normal operating temperature, air cleaner on, choke open, and air conditioning off, unless otherwise noted. Set the parking brake and block the rear wheels. Automatic transmissions should be set in Drive, manuals in Neutral, unless otherwise noted in the procedures or on the emission control label.

1 PREPARE VEHICLE FOR ADJUSTMENTS - SEE EMISSION LABEL ON VEHICLE NOTE IGNITION TIMING SET_ PER LABEL

84903157

Fig. 112 Adjusting the valve—gasoline engines

3 SOLENOID ENERGIZED A / C COMPRESSOR LEAD DISCONNECTED AT A7C COMPRESSOR, A7C ON, A/T TRANSMISSION IN DRIVE

Fig. 1131 le speed adjustment—4.81 engines

I. PREPARE VEHICLE FOR ADJUSTMENTS - SEE EMISSION LABEL ON VEHICL NOTE IGNITION TIMING SET PER LABEL

5. TURN SCREW TO ADJUST TO SPECIFIED PRM. (RECONNECT A/C COMPRESSOR LEAD AFTER ADJUSTMENT) ELECTRICAL CONNECTION 4 OPEN THROTTLE SLIGHTLY TO ALLOW SOLENOID PLUNGER TO FULLY EXTEND

2 TURN IDLE SPEED SCRE TO SET CURB IDLE SPEED SPECIFICATIONS - AyC OF (SEE EMISSION LABEL)

Fig. 115 Idle speed adjustment—5.7L engines with solenoid

Fig. 114 Idle speed adjustment—5.7L engines without solenoid

2. Refer to the underhood emission sticker and prepare the vehicle for adjustment as specified on the sticker. On models without a solenoid, turn the idle speed screw to obtain the idle speed listed in the underhood emission control label. On models with a solenoid, turn the solenoid screw to obtain the idle speed listed in the underhood emission control label. Disconnect the wire at the air conditioning compressor and turn the ait conditioning on. Rev the engine momentarily to fully extend the solenoid plunger. Turn the solenoid screw to obtain the solenoid idle speed listed on the underhood emission sticker. Reconnect the air conditioning wire at the compressor. GASOLINE FUEL INJECTED ENGINES The fuel injected vehicles are controlled by a computer which supplies the correct amount of fuel during all engine operating conditions and controls idle speed; no adjustment is necessary or possible.

GENERAL INFORMATION AND MAINTENANCE DIESEL ENGINES SOLENOID - FAST IDLE

Idle Speed > See Figure 116 ••A special tachometer suitable for diesel engines must be used. A gasoline engine type tach will not work with the diesel engine. 1. Set the parking brake and block the drive wheels. 2. Run the engine up to normal operating temperature. The air cleaner must be mounted and all accessories turned off. 3. Install the diesel tachometer as per the manufacturer's instructions. 4. Adjust the low idle speed screw on the fuel injection pump to the specification listed on the underhood label in Neutral or P for both manual and automatic transmissions.

SCREW - LOW IDLE

Fig. 116 Idle speed adjustment—diesel engines

GASOLINE TUNE-UP SPECIFICATIONS*

Year 1988

1989

1990

1991

1992

Engine Spark Plugs Gap Engine Displacement (in.) ID/VIN Liters (cc) 4.3 (4293) 4.8(4785) 5.0 (4999) 5.7 (5735) 7.4 (7440) 7.4 (7440)

0.040 0.035 0.045 0.045 0.045 0.045

® 88 4B 4B 4B 4B

Z T" H K N W

4.3 (4293) 4.8 (4785) 5.0 (4999) 5.7 (5735) 7.4 (7440) 7.4 (7440)

0.040 0.035 0.035 0.035 0.035 0.035

® 88 4B 4B 4B 4B

Z T H

4.3 (4293)

0.040 0.035 0.035

4.8 (4785) 5.0 (4999)

5.7(5735)

0.035

N W

7.4 (7440) 7.4 (7440)

Z H K N Z K

1994

1995

1996

Z T H K N W

1993

Ignition Timing (deg.)

N Z

Idle Speed (rpm)

Fuel Pump AT ® 8B 4B 4B 48 4B ® 8B 48 4B 4B

(PSl)

9-13

5.0 h4.0-6.5 1

4.0-6.5 9-13

4.0-6.5

MT 700 700 700 700 700 700

AT 700 700 700 700 700 700

700_j 700 700 700 700 700

700 700 700 700 700 700

Valve Clearance In. Ex. HYD HYD HYD HYD HYD HYD HYD HYD HYD HYD HYD HYD

4.0-6.5

® ®

9-13

® ®

9-13

HYD HYD HYD HYD HYD HYD HYD HYD HYD HYD HYD HYD HYD JHYD HYD HYD HYD HYD

9-13

HYD

0.035 0.035

® ®

9-13

5.0

® ®

HYD HYD HYD HYD ^HYD

4.3(4293)

0.040

9-13

HYD

5.0(4999)

0.035 0.035 0.035

® ® ® ® ® ® ® ® ® ® ® ® ® ® ® ® ® ® ® ® ® ® ®

9-13

HYD

® ®

9-13

® ®

9-13

® ®

HYD HYD HYD

9-13

HYD

® ®

9-13

HYD

9-13

HYD

HYD HYD

9-13

HYD

9-13

HYD

9-13

HYD

9-13

HYD

® ® ® ®

9-13

® ®

9-13

® ® ® ®

HYD HYD HYD HYD HYD HYD

HYD HYD HYD HYD

® ®

® ® ® ® ® ®

® ®

9-13

® ®

HYD

9-13

HYD

6CV66

HYD

60-66

HYD

6066

HYD

60-66

HYD

5.7 (5735) 7.4 (7440) 4.3(4293) 5.0(4999) 5.7 (5735) 7.4 (7440) 4.3 (4293)

5.0 (4999)

5.7(5735)

N Z H

7.4 (7440)

0.035 0.035 0.035 0.035 0.035 0.035 0.035 0.035

K N Z H

4.3(4293) 5.0 (4999) 5.7 (5735) 7.4 (7440) 4.3 (4293) 5.0 (4999)

0.035 0.035 0.035 0.035

0.035 0.035

0.045 0.035

5.7 (5735)

7.4 (7440)

4.3 (4293)

5.0 (4999)

0.060 0.060

5.7 (5735)

0.060

7.4 (7440)

0.060

9-13

5.0 4.0-6.5 4.0-6.5 9-13

9-13 9-13 9-13 9-13

HYD HYD

*Refer to the Vehicle Emissions Control Information label in the engine compartment; use the information there if it differs from that listed here.

1-31

1-32 GENERAL INFORMATION AND MAINTENANCE GASOLINE TUNE-UP SPECIFICATIONS

Year 1997

1998

Engine Spark Plugs Engine Displacement Gap IDA/IN Liters (cc) (in.) W 4.3 (4293) 0.035 M

5.0 (4999)

0.045

5.7 (5735)

0.045

7.4 (7440)

0.045

4.3 (4293)

0.035

5.0 (4999)

0.045

5.7 (5735)

0.045

Ign tion Tim ing (de g.) MT ® ® ® ® ® ® ® ®

AT ® ® ® ® ® ® ® ®

Fuel Pump (psi) 60-66

Idle Speed (rpm) MT ®

60-66 60-66 60-66 60-66 60-66 60-66

7.4 (7440) 0.045 60-66 NOTE: The Vehicle Emission Control Information label often rellei s specification changes made during production.

® ® ® ® CD ®

AT ® ® ® ® ® ® ® ®

Valve Clearance In. Ex. HYD HYD

HYD

The label figures must be used if they differ from those in this cha HYD—Hydraulic

(D Refer to the underhood label

NA—Not Available

•"All idle speeds are to be set within 25 rpm of the specified va ies.

5. Adjust the fast idle speed as follows: a. Remove the connector from the fast idle solenoid. Use an insi ated jumper wire from the battery positive terminal to the solenoid termin to energize the solenoid. b. Open the throttle momentarily to ensure that the fast idle solei old plunger is energized and fully extended. c. Adjust the extended plunger by turning the hex-head screw to an engine speed of 800 rpm (check the underhood label) in Neutral. d. Remove the jumper wire and reinstall the connector to the fast idle solenoid. 6. Disconnect and remove the tachometer.

Air Conditioning System SYSTEM SERVICE & REPAIR ••It is recommended that the A/C system be serviced by an EPA (lection 609 certified automotive technician utilizing a refrigerant recovel y/recycling machine.

The do-it-yourselfer should not service his/her own vehicle's A/C sy tern for many reasons, including legal concerns, personal injury, environmenta damage and cost. According to the U.S. Clean Air Act, it is a federal crime to service o 1 repair (involving the refrigerant) a Motor Vehicle Air Conditioning (MVAC) sy: lem for money without being EPA certified. It is also illegal to vent R-12 and RJ 34a refrigerants into the atmosphere. State and/or local laws may be more s rict than the federal regulations, so be sure to check with your state and/or local luthorities for further information. ••Federal law dictates that a fine of up to $25,000 may be leviei on people convicted of venting refrigerant into the atmosphere. When servicing an A/C system you run the risk of handling or comii g in contact with refrigerant, which may result in skin or eye irritation or fro$ bite. Although low in toxicity (due to chemical stability), inhalation of concentrated refrigerant fumes is dangerous and can result in death; cases of fatal caidiac arrhythmia have been reported in people accidentally subjected to high evels of refrigerant. Some early symptoms include loss of concentration and drowsiness. '••Generally, the limit for exposure is lower for R-134a than it is or R12. Exceptional care must be practiced when handling R-134a.

Also, some refrigerants can decompose at high temperatures (near gas heaters or open flame), which may result in hydrofluoric acid, hydrochli: ric acid and phosgene (a fatal nerve gas). It is usually more economically feasible to have a certified MVAC automotive technician perform A/C system service on your vehicle.

R-12 Refrigerant Conversion If your vehicle still uses R-12 refrigerant, one way to save A/C system costs down the road is to investigate the possibility of having your system converted to R-134a. The older R-12 systems can be easily converted to R-134a refrigerant by a certified automotive technician by installing a few new components and changing the system oil. The cost of R-12 is steadily rising and will continue to increase, because it is no longer imported or manufactured in the United States. Therefore, it is often possible to have an R-12 system converted to R-134a and recharged for less than it would cost to just charge the system with R-12. If you are interested in having your system converted, contact local automotive service stations for more details and information. PREVENTIVE MAINTENANCE Although the A/C system should not be serviced by the do-it-yourselfer, preventive maintenance should be practiced to help maintain the efficiency of the vehicle's A/C system. Be sure to perform the following: • The easiest and most important preventive maintenance for your A/C system is to be sure that it is used on a regular basis. Running the system for five minutes each month (no matter what the season) will help ensure that the seals and all internal components remain lubricated. ••Some vehicles automatically operate the A/C system compressor whenever the windshield defroster is activated. Therefore, the A/C system would not need to be operated each month if the defroster was used.

• In order to prevent heater core freeze-up during A/C operation, it is necessary to maintain proper antifreeze protection. Be sure to properly maintain the engine cooling system. • Any obstruction of or damage to the condenser configuration will restrict air flow which is essential to its efficient operation. Keep this unit clean and in proper physical shape. ••Buq screens which are mounted in front of the condenser (unless they are original equipment) are regarded as obstructions.

• The condensation drain tube expels any water which accumulates on the bottom of the evaporator housing into the engine compartment. If this tube is obstructed, the air conditioning performance can be restricted and condensation buildup can spill over onto the vehicle's floor. SYSTEM INSPECTION Although the A/C system should not be serviced by the do-it-yourselfer, system inspections should be performed to help maintain the efficiency of the vehicle's A/C system. Be sure to perform the following:

GENERAL INFORMATION AND MAINTENANCE The easiest and often most important check for the air conditioning system consists of a visual inspection of the system components. Visualiy inspect the system for refrigerant leaks, damaged compressor clutch, abnormal compressor drive belt tension and/or condition, plugged evaporator drain tube, blocked condenser fins, disconnected or broken wires, blown fuses, corroded connections and poor insulation. A refrigerant leak will usually appear as an oily residue at the leakage point in the system. The oily residue soon picks up dust or dirt particles from the surrounding air and appears greasy. Through time, this will build up and appear to be a heavy dirt impregnated grease. For a thorough visual and operational inspection, check the following: • Check the surface of the radiator and condenser for dirt, leaves or other material which might block air flow. • Check for kinks in hoses and lines. Check the system for leaks. • Make sure the drive belt is properly tensioned. During operation, make sure the belt is free of noise or slippage. • Make sure the blower motor operates at all appropriate positions, then check for distribution of the air from all outlets. ••Remember that in high humidity, air discharged from the vents may not feel as cold as expected, even if the system is working properly. This is because moisture in humid air retains heat more effectively than dry air, thereby making humid air more difficult to cool.

1-33

streaking, smearing and blade deterioration if left on the glass. It is advisable to wash the windshield carefully with a commercial glass cleaner at least once a month. Wipe off the rubber blades with the wet rag afterwards. Do not attempt to move wipers across the windshield by hand; damage to the motor and drive mechanism will result. To inspect and/or replace the wiper blade elements, place the wiper switch in the LOW speed position and the ignition switch in the ACC position. When the wiper blades are approximately vertical on the windshield, turn the ignition switch to OFF. Examine the wiper blade elements. If they are found to be cracked, broken or torn, they should be replaced immediately. Replacement intervals will vary with usage, although ozone deterioration usually limits element life to about one year. If the wiper pattern is smeared or streaked, or if the blade chatters across the glass, the elements should be replaced. It is easiest and most sensible to replace the elements in pairs. If your vehicle is equipped with aftermarket blades, there are several different types of refills and your vehicle might have any kind. Aftermarket blades and arms rarely use the exact same type blade or refill as the original equipment. Regardless of the type of refill used, be sure to follow the part manufacturer's instructions closely. Make sure that all of the frame jaws are engaged as the refill is pushed into place and locked. If the metal blade holder and frame are allowed to touch the glass during wiper operation, the glass will be scratched.

Tires and Wheels

Windshield Wipers

Common sense and good driving habits will afford maximum tire life. Make sure that you don't overload the vehicle or run with incorrect pressure in the tires. Either of these will increase tread wear. Fast starts, sudden stops and sharp cornering are hard on tires and will shorten their useful life span.

ELEMENT (REFILL) CARE & REPLACEMENT » See Figures 117,118 and 119 For maximum effectiveness and longest element life, the windshield and wiper blades should be kept clean. Dirt, tree sap, road tar and so on will cause

••For optimum tire life, keep the tires properly inflated, rotate them often and have the wheel alignment checked periodically. Inspect your tires frequently. Be especially careful to watch for bubbles in the tread or sidewall, deep cuts or underinfiation. Replace any tires with bubbles in the sidewall. If cuts are so deep that they penetrate to the cords, discard the tire. Any cut in the sidewall of a radial tire renders it unsafe. Also look for uneven tread wear patterns that may indicate the front end is out of alignment or that the tires are out of balance. TIRE ROTATION » See Figure 120

ADAPTERS Fig. 117 Most aftermarket blades are available with multiple adapters to fit different vehicles

Tires must be rotated periodically to equalize wear patterns that vary with a tire's position on the vehicle. Tires will also wear in an uneven way as the front steering/suspension system wears to the point where the alignment should be reset. Rotating the tires will ensure maximum life for the tires as a set, so you will not have to discard a tire early due to wear on only part of the tread. Regular rotation is required to equalize wear. When rotating "unidirectional tires," make sure that they always roll in the same direction. This means that a tire used on the left side of the vehicle must not be switched to the right side and vice-versa. Such tires should only be

Front

• i Fig. 118 Choose a blade which will fit your vehicle, and that will be readily available next time you need blades

(FORNON DIRECTIONAL TIRES AND WHEELS)

Front

(FOR

DIRECTIONAL TIRES AND WHEELS)

FCCS1231

Fig. 119 When installed, be certain the blade is fully inserted into the backing

Fig. 120 Compact spare tires must NEVER be used in the rotation pattern

1-34 GENERAL INFORMATION AND MAINTENANCE rotated front-to-rear or rear-to-front, while always remaining on the sam|j side of the vehicle. These tires are marked on the sidewall as to the direction of rotation; observe the marks when reinstalling the tire(s). Some styled or "mag" wheels may have different offsets front to rear :|n these cases, the rear wheels must not be used up front and vice-versa. Further these wheels are equipped with unidirectional tires, they cannot be rotatf j unless the tire is remounted for the proper direction of rotation, ••The compact or space-saver spare is strictly for emergency use It must never be included in the tire rotation or placed on the vehicl jfor everyday use.

ing and braking characteristics of the vehicle. Once the snow tires are installed, you must re-learn the behavior of the vehicle and drive accordingly. •••Consider buying extra wheels on which to mount the snow tires. Once done, the "snow wheels" can be installed and removed as needed. This eliminates the potential damage to tires or wheels from seasonal removal and installation. Even if your vehicle has styled wheels, see if inexpensive steel wheels are available. Although the look of the vehicle will change, the expensive wheels will be protected from salt, curb hits and pothole damage. TIRE STORAGE

TIRE DESIGN I See Figure 121 For maximum satisfaction, tires should be used in sets of four, ferent brands or types (radial, bias-belted, fiberglass belted) should be a In most cases, the vehicle manufacturer has designated a type of tire on the vehicle will perform best. Your first choice when replacing tires shoi use the same type of tire that the manufacturer recommends. When radial tires are used, tire sizes and wheel diameters should be: ilected to maintain ground clearance and tire load capacity equivalent to the ork nal specified tire. Radial tires should always be used in sets of four.

CAUTION Radial tires should never be used on only the front axle. When selecting tires, pay attention to the original size as marked on t e tire. Most tires are described using an industry size code sometimes referred o as P-Metric. This allows the exact identification of the tire specifications, regardless of the manufacturer. If selecting a different tire size or brand, rememher to check the installed tire for any sign of interference with the body or susp nsion while the vehicle is stopping, turning sharply or heavily loaded.

Snow Tires Good radial tires can produce a big advantage in slippery weather, bu in snow, a street radial tire does not have sufficient tread to provide tractior and control. The small grooves of a street tire quickly pack with snow and thi tire behaves like a billiard ball on a marble floor. The more open, chunky tre; d of a snow tire will self-clean as the tire turns, providing much better grip on: nowy surfaces To satisfy municipalities requiring snow tires during weather erherger ies, most snow tires carry either an M + S designation after the tire size starr ied on the sidewall, or the designation "all-season." In general, no change in tin; size is necessary when buying snow tires Most manufacturers strongly recommend the use of 4 snow tires on t jeir vehicles for reasons of stability. If snow tires are fitted only to the drive v leels, the opposite end of the vehicle may become very unstable when braking ir turning on slippery surfaces. This instability can lead to unpleasant endi gs i the driver can't counteract the slide in time. Note that snow tires, whether 2 or 4, will affect vehicle handling in all ponsnow situations. The stiffer, heavier snow tires will noticeably change the|turnMETRIC TIRE SIZES

Fig. 121 P-Metric tire coding

If they are mounted on wheels, store the tires at proper inflation pressure. All tires should be kept in a cool, dry place. If they are stored in the garage or basement, do not let them stand on a concrete floor; set them on strips of wood, a mat or a large stack of newspaper. Keeping them away from direct moisture is of paramount importance. Tires should not be stored upright, but in aflat position. INFLATION & INSPECTION I See Figures 122 thru 127 The importance of proper tire inflation cannot be overemphasized. A tire employs air as part of its structure. It is designed around the supporting strength of the air at a specified pressure. For this reason, improper inflation drastically reduces the tire's ability to perform as intended. A tire will lose some air in day-to-day use; having to add a few pounds of air periodically is not necessarily a sign of a leaking tire. Two items should be a permanent fixture in every glove compartment: an accurate tire pressure gauge and a tread depth gauge. Check the tire pressure (including the spare) regularly with a pocket type gauge. Too often, the gauge on the end of the air hose at your corner garage is not accurate because it suffers too much abuse. Always check tire pressure when the tires are cold, as pressure increases with temperature. If you must move the vehicle to check the tire inflation, do not drive more than a mile before checking, A cold tire is generally one that has not been driven for more than three hours. A plate or sticker is normally provided somewhere in the vehicle (door post, hood, tailgate or trunk lid) which shows the proper pressure for the tires. Never counteract excessive pressure buiid-up by bleeding off air pressure (letting seme air out). This will cause the tire to run hotter and wear quicker.

#* CAUTION Never exceed the maximum tire pressure embossed on the tire! This is the pressure to be used when the tire is at maximum loading, but it is rarely the correct pressure for everyday driving. Consult the owner's manual or the tire pressure sticker for the correct tire pressure. Once you've maintained the correct tire pressures for several weeks, you'll be familiar with the vehicle's braking and handling personality. Slight adjustments in tire pressures can fine-tune these characteristics, but never change the cold pressure specification by more than 2 psi. A slightly softer tire pressure will give a softer ride but also yield lower fuel mileage. A slightly harder tire will give crisper dry road handling but can cause skidding on wet surfaces. Unless you're fully attuned to the vehicle, stick to the recommended inflation pressures. All automotive tires have built-in tread wear indicator bars that show up as 1/2 in. (13mm) wide smooth bands across the tire when Vie in. (1,5mm) of tread remains. The appearance of tread wear indicators means that the tires should be replaced. In fact, many states have laws prohibiting the use of tires with less than this amount of tread. You can check your own tread depth with an inexpensive gauge or by using a Lincoln head penny. Slip the Lincoln penny (with Lincoln's head upside-down) into several tread grooves. If you can see the top of Lincoln's head in 2 adjacent grooves, the tire has less than Vie in. (1.5mm) tread left and should be replaced. You can measure snow tires in the same manner by using the "tails" side of the Lincoln penny. If you can see the top of the Lincoln memorial, it's time to replace the snow tire(s).

GENERAL INFORMATION AND MAINTENANCE

1-35

â&#x20AC;˘HAVE TIRF INSPECTED FOR FURTHFR USE

Fig. 122 Common tire wear patterns and causes

PROPERLY INFLATFD

Fig. 123 Tires with deep cuts, or cuts which bulge, should be replaced immediately

IMPROPERLY INFLATED

Fig. 124 Radial tires have a characteristic sidewall bulge; don't try to measure pressure by looking at the tire. Use a quality air pressure gauge

Fig. 126 Accurate tread depth indicators are inexpensive and handy

Fig. 125 Tread wear indicators will appear when the tire is worn

Fig. 127 A penny works well for a quick check of tread depth

FLUIDS AND LUBRICANTS

Fluid Disposal Used fluids such as engine oil, transmission fluid, antifreeze and brake fluid are hazardous wastes and must be disposed of properly. Before draining any fluids, consult with your local authorities; in many areas, waste oil, antifreeze, etc. is being accepted as a part of recycling programs. A number of service stations and auto parts stores are also accepting waste fluids for recycling. Be sure of the recycling center's policies before draining any fluids, as many will not accept different fluids that have been mixed together.

Fuel and Oil Recommendations OIL I See Figures 128,129 and 130

The Society of Automotive Engineers (SAE) grade number indicates the viscosity of the engine oil; its resistance to flow at a given temperature. The lower

the SAE grade number, the lighter the oil. For example, the mono-grade oils begin with SAE 5 weight, which is a thin light oil, and continue in viscosity up to SAE 80 or 90 weight, which are heavy gear lubricants. These oils are also known as "straight weight", meaning they are of a single viscosity, and do not vary with engine temperature. Multi-viscosity oils offer the important advantage of being adaptable to temperature extremes. These oils have designations such as 10W-40,20W-50, etc. The 10W-40 means that in winter (the "W" in the designation) the oil acts like a thin 10 weight oil, allowing the engine to spin easily when cold and offering rapid lubrication. Once the engine has warmed up, however, the oil acts like a straight 40 weight, maintaining good lubrication and protection for the engine's internal components. A 20W-50 oil would therefore be slightly heavier than and not as ideal in cold weather as the 10W-40, but would offer better protection at higher rpm and temperatures because when warm it acts like a 50 weight oil. Whichever 011 viscosity you choose when changing the oil, make sure you are anticipating the temperatures your engine will be operating in until the oil is changed again Refer to the oil viscosity chart for oil recommendations according to temperature. The American Petroleum Institute (API) designation indicates the classification of engine oil used under certain given operating conditions. Only oils designated for

1-36

GENERAL INFORMATION AND MAINTENANCE

HOT WEATHER HOT WEATHER

JEfl SAE 10W-30 SAE 5W-30 PREFERRED COLD WEATHER

SAE 15W-40 •PREFERRED

IF NEI™ER SAE 5W-30 NQR SA£ ,„„,_,„

GRADE OILS ARE AVAILABLE, SAE 30 GRADE MAY BE USED AT TEMPERATURES ABOVE 40'F (4°C)

SAE 10W-30

OQN'TPQLL T£, CONSERVE RESOURCES,

TURN USI 3 OIL TO COLLECTION CENTERS

COLD WEATHER

Do Not Use SAE 10W-40 Grade Oil or any Other Grade Not Recommended. 84901

TCCS1235

Fig. 128 Gasoline engine oil viscosity chart

Fig. 129 Lcok for the API oil identification

label whe choosing your engine oil

Fig. 130 Diesel engine oil viscosity chart

RECOMMENDED LUBRICANTS

Component Engine Oil Coolant Manual Transmission Muncie 117mm Getrag 85mm NVG 4500 NVG5LM60 Automatic Transmission Transfer Case Differential Master Cylinder Power Steering Manual Steering Gear Multi-Purpose Grease

use "Service SG, SH" or greater should be used. Oils of the SG, SH or its SL lerseding oil type perform a variety of functions inside the engine in addition to the basic function as a lubricant. Through a balanced system of metallic detergents an I polymeric dispersants, the oil prevents the formation of high and low temperatur deposits and also keeps sludge and particles of dirt in suspension. Acids, p;i licularly sulfuric acid, as well as other by-products of combustion, are neutralize i. Both the SAE grade number and the APE designation can be found on top of the i il can Diesel engines also require SG, SH or greater engine oil. In addition, the >il must qualify for a CC or greater rating. The API has a number of different diesel er gine ratings, including CB, CC, and CD. Any of these other oils are fine as long a:; the designation CC appears on the container label along with them. Do not use labeled only SG, SH or only CC. Both designations must always appear togf • he; For recommended oil viscosities, refer to the chart. Note that 10W-3C and 10W-40 grade oils are not recommended for sustained high speed driving when the temperature rises above the indicated limit.

Lubricant API SG/CE EthyleneGlycol Anti-Freeze API GL5, SAE 80W-90 Synchromesh Transmission Fluid Castrol Syntorq GL-4 Synchromesh Transmission Fluid AFT Dexron® I APIGL-5, SAE80W-90 DOT 3 Brake Fluid GM Power Steering Fluid GM Lubricant NLGI#2

Gasoline Engines

determines the speed at which the gas will burn. The lower the octane rating, the faster it burns. The higher the octane, the slower the fuel will burn and a greater percentage of compounds in the fuel prevent spark ping (knock), detonation and preignition (dieseling). As the temperature of the engine increases, the air/fuel mixture exhibits a tendency to ignite before the spark plug is fired. If fuel of an octane rating too lew for the engine is used, this will allow combustion to occur before the piston has completed its compression stroke, thereby creating a very high pressure very rapidly. Fuel of the proper octane rating, for the compression ratio and ignition timing ol your truck, will slow the combustion process sufficiently to allow the spark plug enough time to ignite the mixture completely and smoothly. Many non-catalyst models are designed to run on regular fuel. The use of some super-premium fuel is no substitution for a properly tuned and maintained engine. Chances are that if your engine exhibits any signs of spark ping, detonation or pre-ignition when using regular fuel, the ignition timing should be checked against specifications or the cylinder head should be removed for decarbonizing. Vehicles equipped with catalytic converters must use UNLEADED GASOLINE ONLY. Use of unleaded fuel shortened the life of spark plugs, exhaust systems and EGR valves and can damage the catalytic converter. Most converter equipped models are designed to operate using unleaded gasoline with a minimum rating of 87 octane. Use of unleaded gas with octane ratings lower than 87 can cause persistent spark knock which could lead to engine damage. Light spark knock may be noticed when accelerating or driving up hills. The slight knocking may be considered normal (with 87 octane) because the maximum fuel economy is obtained under condition of occasional light spark knock. Gasoline with an octane rating higher than 87 may be used, but it is not necessary (in most cases) for proper operation. If spark knock is constant, when using 87 octane, at cruising speeds on level ground, ignition timing adjustment may be required.

It is important to use fuel of the proper octane rating in your truck. Oc „„.ane rating is based on the quantity of anti-knock compounds added to the fuel and

'•Your engine's fuel requirement can change with time, mainly due to carbon buildup, which changes the compression ratio. If your engine

Synthetic Oil There are many excellent synthetic and fuel-efficient oils currently av; liable that can provide better gas mileage, longer service life, and in some cas s better engine protection. These benefits do not come without a few hitches, ho (ever; the main one being the price of synthetic oils, which in most cases is mi: re expensive per quart of conventional oil. Synthetic oil is not for every truck and every type of driving, so you s ould consider your engine's condition and your type of driving. Also, check yi: ur truck's warranty conditions regarding the use of synthetic oils. FUEL

GENERAL INFORMATION AND MAINTENANCE

1-37

pings, knocks or runs on, switch to a higher grade of fuel. Sometimes just changing brands will cure the problem. If it becomes necessary to retard the timing from specifications, don't change it more than a few degrees. Retarded timing will reduce power output and fuel mileage and will increase the engine temperature.

• Remove oil from skin by washing thoroughly with soap and water or waterless hand cleaner. Do not use gasoline, thinners or other solvents. • Avoid prolonged skin contact with oil-soaked clothing.

Diesel Engines

I See Figures 131,132 and 133

Diesel engines require the use of diesel fuel. At no time should gasoline be substituted. Two grades of diesel fuel are manufactured, No. 1 and No. 2, although No. 2 grade is generally more available. Better fuel economy results from the use of No. 2 grade fuel. In some northern parts of the U.S. and in most parts of Canada, No. 1 grade fuel is available in the winter or a winterized blend of No. 2 grade is supplied in winter months. When the temperature falls below 20F (-7C), No. 1 grade or winterized No. 2 grade fuel are the only fuels that can be used. Cold temperatures cause unwinterized No. 2 to thicken (it actually gels), blocking the fuel lines and preventing the engine from running. • Do not use home heating oil in your truck. • Do not use ether or starting assist fluids in your truck. • Do not use any fuel additives recommended for use in gasoline engines. It is normal that the engine noise level is louder during the warm-up period in winter. It is also normal that whitish/blue smoke may be emitted from the exhaust after starting and during warm-up. The amount of smoke depends upon the outside temperature.

Every time you stop for fuel, check the engine oil as follows: 1. Park the truck on level ground. 2. When checking the oil level it is best for the engine to be at operating temperature, although checking the oil immediately after a stopping will lead to a false reading. Wait a few minutes after turning off the engine to allow the oil to drain back into the crankcase. 3. Open the hood and locate the dipstick which is on the left side of the engine. Pull the dipstick from its tube, wipe it clean and reinsert it. 4. Pull the dipstick out again and, holding it horizontally, read the oil level. The oil should be between the FULL or OPERATING RANGE and ADD or ADD OIL marks on the dipstick. 5. If "he oil is below the ADD mark, add oil of the proper viscosity through the capped opening on the top of the cylinder head cover. See the "Oil and Fuel Recommendations" chart in this section for the proper viscosity and rating of acceptable oils. 6. Reinsert the dipstick and check the oil level again after adding any oil. Be careful not to overfill the crankcase. Approximately one quart of oil will raise the level from the ADD to the FULL. Excess oil will generally be consumed at an accelerated rate.

Engine ** CAUTION

OIL & FILTER CHANGE

Prolonged and repeated skin contact with used engine oil, with no effort to remove the oil, may be harmful. Always follow these simple precautions when handling used motor oil: • Avoid prolonged skin contact with used motor oil.

OIL LEVEL CHECK

» See Figures 134,135,136 and 137 The oil should be changed every 7500 miles (12,000 km). General Motors recommends changing the oil filter with every other oil change; we suggest that the filter be changed with every oil change. There is approximately 1 quart of

Fig. 131 Remove the oil dipstick and check the oil level

Fig. 132 Remove the oil filler cap

Fig. 133 Using a funnel, add the proper grade and viscosity of oil

Fig. 134 With the proper size socket, loosen the drain plug

Fig. 135 Remove the drain plug while maintaining a slight upward force, to keep the oil from running out prematurely

Fig. 136 With a filter wrench, loosen the oil filter counterclockwise

1-38

GENERAL INFORMATION AND MAINTENANCE 12. Open a container of new oil and smear some of this oil onto the rubber gasket of the new oil filter. Get a feel for where the filter post is and start the filter by hand until the gasket contacts the seat. Turn the filter an additional % turn with your hand. 13. Install the drain plug and metal gasket. Be sure that the plug is tight enough that the oil does not leak out, but not tight enough to strip the threads. Over time you will develop a sense of what the proper tightness of the drain plug is. If a torque wrench is available, tighten the plug to 18 ft. Ibs. (25 Nm). —Replace the drain plug gasket at every third or fourth oil change.

Fig. 137 Before installing a new oil filter, coat the rubber gaskei with clean oil dirty oil left remaining in the old oil filter if it is not changed! A few doll; every year seems a small price to pay for extended engine life—so chan filter every time you change the oil! The oil drain plug is located on the bottom, rear of the oil pan (botton engine, underneath the truck). The mileage figures given are the recommended intervals assuming n driving and conditions. If your truck is being used under dusty, polluted road conditions, change the oil and filter more frequently than specified same goes for trucks driven in stop-and-go traffic or only for short dista Always drain the oil after the engine has been running long enough to b normal operating temperature. Hot oil will flow easier and more contami will be removed along with the oil than if it were drained cold. To chang and filter:

more ethe

—If the engine is equipped with an oil cooler, this will also have drained, using the drain plug. Be sure to add enough oil to fill tin cooler in addition to the engine.

1. Warm the oil by running the engine for a short period of time or until the needle on the temperature gauge rises above the C mark. This v make the oil flow more freely from the oil pan. 2. Park on a level surface, apply the parking brake and block the wi 3. Stop the engine. Raise the hood and remove the oil filler cap fro top of the valve cover. This allows the air to enter the engine as the oil d Remove the dipstick, wipe it off and set it aside. 4. Position a suitable oil drain pan under the drain plug.

least

of the rmal r offhe es. ig it to nts he oil

14. Through a suitable plastic or metal funnel, add clean new oil of the proper grade and viscosity through the oil filler on the top of the valve cover. Be sure that the oil level registers near the (full) mark on the dipstick. 15. Install and tighten the oil filler cap. 16. Start the engine and allow it to run for several minutes. Check for leaks at the filter and drain plug. Sometimes leaks will not be revealed until the engine reaches normal operating temperature. 17. Stop the engine and recheckthe oil level. Add oil as necessary. When you have finished this job, you will notice that you now possess several quarts of dirty oil. The best thing to do with it is to pour it into plastic jugs, such as milk or anti-freeze containers. Then, find a gas station or service garage which accepts waste oil for recycling and dispose of it there.

Manual Transmission FLUID RECOMMENDATION • • • • •

Muncie 117mm: API GL-5, SAE80W-90 Getrag 85mm: Syncromesh Transmission Fluid NVG 4500: Castrol Syntorq GL-4 NVG 5LM60: Syncromesh Transmission Fluid NVG 3500: Syncromesh Transmission Fluid

LEVEL CHECK els. the ins.

—All diesel and gasoline engines hold approximately 5-8 quarts oil (give or take), so choose a drain pan that exceeds this amount to How for movement of the oil when the pan is pulled from under the ve cle. This will prevent time lost to the cleaning up of messy oil spills. 5. With the proper size socket or wrench (DO NOT use pliers or vis grips), loosen the drain plug. Back out the drain plug while maintaining a sligh pward force on it to keep the oil from running out around it (and your hand). A wthe oil to drain into the drain pan.

CAUTION

»See Figure 138 Check the lubricant level at least twice a year, even more frequently if driven in deep water. 1. With the truck parked on a level surface, remove the filler plug from the side of the transmission case. Be careful not to take out the drain plug at the bottom. 2. If lubricant begins to trickle out of the hole, there is enough. If not, carefully insert a finger (watch out for sharp threads) and check that the level is up to the edge of the hole. 3. If not, add sufficient lubricant with a funnel and tube, or a squeeze bulb to bring it to the proper level. You can also use a common kitchen baster. 4. Install the plug and tighten to 17 ft. Ibs. (23 Nm) on the Muncie and Getrag; 30 ft. Ibs. (40 Nm) on NVG 4500; and 44 ft. Ibs. (60 Nm) on the NVG 5LM60. Road test the truck and check for any leaks.

The engine oil will be hot. Keep your arms, face and hands away from the oil as it is draining. 6. Remove the drain pan and wipe any excess oil from the area arou d the hole using a clean rag. 7. Clean the threads of the drain plug and the drain plug gasket to re nove any sludge deposits that may have accumulated. 8. Place the drain pan under the oil filter location to prevent spilling any oil from the filter on to the ground. 9. With a filter wrench, loosen the oil filter counterclockwise and back the filter off the filter post the rest of the way by hand. Keep the filter end up so that the oil does not spill out. Tilt the filter into the drain pan to drain the oil. 10. Remove the drain pan from under the vehicle and position it off to the side. 11. With a clean rag, wipe off the filter seating surface to ensure a proi: er seal. Make sure that the old gasket is not stuck to the seating surface. If it s, remove it and thoroughly clean the seating surface of the old gasket mater al.

84901096

Fig. 138 Use your finger to check the oil level in the manual transmission

GENERAL INFORMATIONAND MAINTENANCE DRAIN & REFILL No intervals are specified for changing the transmission lubricant, but it is a good idea on a used vehicle, one that has been worked hard, or one driven in deep water. The vehicle should be on a level surface and the lubricant should be at operating temperature. 1. Position the truck on a level surface. 2. Place a pan of sufficient capacity under the transmission drain plug. 3. Remove the upper (fill) plug to provide a vent opening. 4. Remove the lower (drain) plug and let the lubricant drain out.

** CAUTION The oil will be hot! Be careful when you remove the plug or you'll be taking a bath in hot gear oil. 5. Install the drain plug and tighten to 17 ft. Ibs. (23 Nm) on the Muncie and Getrag; 30 ft. Ibs. (40 Nm) on NVG 4500; and 44 ft. Ibs. (60 Nm) on the NVG 5LM60. 6. Add lubricant with a suction gun or squeeze bulb. 7. Reinstall the filler plug. Run the engine and check for leaks

1-39

has been running at high speed for a long period, in city traffic on a hot day or pulling a trailer, let it cool down for about thirty minutes before checking the level. 1. Park the truck on a level surface with the engine idling. Shift the transmission into P and set the parking brake. 2. Remove the dipstick (on newer models, you may have to flip up the handle first), wipe it clean and reinsert it firmly. Be sure that it has been pushed all the way in. 3. Remove the dipstick and check the fluid level while holding it horizontally. All models have a HOT and a COLD side to the dipstick. • COLD: the fluid level should fall in this range when the engine has been running tor only a short time. • HOT: the fluid level should fall in this range when the engine has reached normal running temperatures. 4 Early models have two dimples below the ADD mark, the level should be between these when the engine is cold. 5. If the fluid level is not within the proper area on either side of the dipstick, pour ATF into the dipstick tube. This is easily done with the aid of a funnel. Check the level often as you are filling the transmission. Be extremely careful not to overfill it. Overfilling will cause slippage, seal damage and overheating. Approximately one pint of ATF will raise the level from one notch to the other.

** WARNING The fluid on the dipstick should always be a bright red color. It if is discolored (brown or black), or smells burnt, serious transmission troubles, probably due to overheating, should be suspected. The transmission should be inspected by a qualified service technician to locale the cause of the burnt fluid.

Automatic Transmission FLUID RECOMMENDATIONS Use Dexron III' or its superseding fluid type.

DRAIN 8, REFILL

LEVEL CHECK > See Figures 142,143,144 and 145 » See Figures 139,140 and 141 Check the level of the fluid at least once a month. The fluid level should be checked with the engine at normal operating temperature and running. If the truck

1. The fluid should be drained with the transmission warm. It is easier to change the fluid if the truck is raised somewhat from the ground, but this is not always easy without a lift. The transmission must be level for it to drain properly.

8/981P27

Fig. 139 Remove the dipstick to check the transmission fluid level

1 Fig. 142 Loosen all the pan bolts

Fig. 140 Hold the dipstick horizontally and check the fluid level

Fig. 141 Use a funnel to add transmission fluid

Fig. 143 Pull one corner of the pan down to drain most of the fluid and remove the pan

Fig. 144 Remove the old pan gasket and clean both gasket mating surfaces

1-40

GENERAL INFORMATION AND MAINTENANCE

84901106

87981P31

Fig. 145 Remove the filter from the transmission

Fig. 146 C eck the transfer case fluid level with our finger

2. Place a shallow pan underneath to catch the transmission fluid (t bout 5 pints). Loosen all the pan bolts, then pull one corner down to drain mos of the fluid. If it sticks, VERY CAREFULLY pry the pan loose. You can buy after arket drain plug kits that makes this operation a bit less messy, once installed •*ll the fluid removed smells burnt, serious transmission trouble: probably due to overheating, should be suspected. 3. Remove the pan bolts and empty out the pan. On some models, ere may not be much room to get at the screws at the front of the pan. 4. Clean the pan with solvent and allow it to air dry. If you use a rag| to wipe it out, you risk leaving bits of lint and threads in the transmission 5. Remove the filter or strainer retaining bolts. On the Turbo Hydra-H/latic 400, there are two screws securing the filter or screen to the valve body, reusable strainer may be found on some models. The strainer may be cle| ned in solvent and air dried thoroughly. The filter and gasket must be replaced. To install: 6. Install a new gasket and filter. 7. Install a new gasket on the pan, and tighten the bolts evenly to 1 ft. Ibs. (25 Nm) in a crisscross pattern. 8. Add DEXRON111 or its superseding type of transmission fluid thr ugh the dipstick tube. The correct amount is in the Capacities Chart. Do not t «rfill. 9. With the gearshift lever in Park, start the engine and let it idle. D not race the engine. 10. Move the gearshift lever through each position, holding the braki Return the lever to Park, and check the fluid level with the engine idling. The level should be between the two dimples on the dipstick, about 1/< in. (6r m) below the ADD mark. Add fluid, if necessary. 11. Check the fluid level after the truck has been driven enough to th oughly warm up the transmission. If the transmission is overfilled, the excess must be drained off. Overfilling causes aerated fluid, resulting in transm Hsion slippage and probable damage.

Transfer Case FLUID RECOMMENDATIONS

Fig. 147 The rear differential filler plug may be in either of these locations

DRAIN & REFILL 1. With the transfer case warmed up, park on a level surface. 2. Slide a pan of a least 6 pts. capacity under the case drain plug. 3. Remove the filler plug from the rear of the transfer case (behind the transmission). Remove the drain plug from the bottom. 4. Wipe the area clean and install the drain plug. 5. Add lubricant with a suction gun or squeeze bulb. 6. When the lubricant level is up to the bottom of the filler hole, install the plug and tighten it to specifications. . 4401 and 4470 models: 18 ft. Ibs. (25 Nm). • NV241 and NV243 models: 35 ft. Ibs. (47 Nm),

Front and Rear Drive Axles FLUID RECOMMENDATIONS Front axles use SAE 80W-90, GL-5 Gear Lubricant. Rear axles use SAE 80W90 gear oil. Posi-traction axles must use special lubricant available from dealers and most auto parts stores. If the special fluid is not used, noise, uneven operation, and damage will result. There is also a Posi-traction additive used to cure noise and slippage. Posi-traction axles have an identifying tag, as well as a warning sticker near the jack or on the rear wheel well. LEVEL CHECK » See Figures 147 and 148 The oil level in the front and/or rear differentials should be checked at least twice a year. If driven in deep water it shoujd be checked immediately afterward. The fluid level in the front axle should be 1/2 in, (13mm) below the filler plug opening. The fluid level in the rear axle should be up to the bottom of the filler plug opening. Lubricant may be added with a suction gun or squeeze bulb.

Use Dexron II5 or its superseding fluid type on models through 1994. pn 1995-98 models, use Dexron III" or its superseding fluid. LEVEL CHECK » See Figure 146 Check the four wheel drive transfer case lubricant at least twice a year. 1. With the truck parked on a level surface, remove the filler plug fronf the rear of the transfer case (behind the transmission). Be careful not to take (ut the drain plug at the bottom. 2. If lubricant trickles out, there is enough. If not, carefully insert a fin ier and check that the level is up to the edge of the hole, EXCEPT in full time our wheel drive cases which should be 1/2 in. (13mm) below the hole. 3. Lubricant may be added, if necessary, with a funnel and tube, or a squeeze bulb, 4. Tighten the plug to 18 ft. Ibs. (25 Nm).

Fig. 148 If necessary, fill with the proper fluid

GENERAL INFORMATION AND MAINTENANCE 1. Park on level ground. 2. Remove the filler plug from the differential housing cover. 3. If lubricant trickles out there is enough. If not, carefully insert a finger and check that the level is up to the bottom of the hole. Locking front hubs should be run in the LOCK position for at least 10 miles (6 km) each month to assure proper lubrication to the front axle. 4. Fill with the proper fluid, install the plug and tighten to: REAR: • 81/2 in.—25 ft. Ibs. (34 Nm) • 91/2 and 10'/2 in—19 ft. Ibs. (24 Nm) • 93/4-101/2in —10ft. Ibs. (14 Nm) « 12 in—35ft. Ibs. (47 Nm) FRONT: . All—80ft. Ibs. (110 Nm) DRAIN & REFILL I See Figures 149,150 and 151 No intervals are specified for changing axle lubricant, but it is a good idea every year or so. If you have driven in water over the axle vents, change the fluid immediately. 1. Park the vehicle on the level with the axles at normal operating temperature. 2. Place a pan of at least 6 pints capacity under the differential housing. 3. Remove the filler plug. 4. If you have a drain plug, remove it. If not, unbolt and remove the differential cover. 5. Install the drain plug, or differential cover. Use a new gasket if the differential cover has been removed. 6. Install the drain plug and tighten it so it will not leak. Do not overtighten. •Hi is usually a good idea to replace the gasket at this time.

Fig. 149 Using a wire brush, clean the bolts and edges of the differential cover

1-41

7. Refill the differential with the proper lubricant—do not overfill! 8. Install the filler plug and tighten both plugs to: REAR: • 8 1 /2in— 25ft. Ibs. (34 Nm) • 91/2 and 10V2 in—19 ft. Ibs. (24 Nm) « 9%-101/2in.—10ft. Ibs. (14 Nm) • 12 in—35ft. Ibs. (47 Nm) FRONT: • All: 80 ft. Ibs. (110 Nm) 9. Road test the truck and check for any leaks.

Cooling System » See Figures 152,153,154,155 and 156 The cooling system was filled at the factory with a high quality coolant solution that is good for year around operation and protects the system from freezing down to -20F (-29C) (-32F/36C in Canada). It is good for two full calendar years or 24,000 miles (38,500 km), whichever occurs first, provided that the proper concentration of coolant is maintained. The hot coolant level should be at the FULL HOT mark on the expansion tank and the cold coolant level should be at the FULL COLD mark on the tank. Do not remove the radiator cap to check the coolant level. FLUID RECOMMENDATIONS On 1988-95 models, the coolant mixture in Chevy/GMC trucks is 50/50 ethylene glycol and water for year round use. Use a good quality anti-freeze with water pump lubricants, rust inhibitors and other corrosion inhibitors along with acid neutralizers. On 1996-98 models, Use a 50/50 mixture of DEX-COOL' coolant and water. Do not mix any other type of coolant with the DEX-COOL® as they are incompatible and may cause damage to the cooling system.

Fig. 150 After removing the bolts, carefully pry the bottom of the cover off and drain the fluid

Fig. 151 After the oil has drained, remove the differential cover

\. 153 Remove any debris from the radiFig. 152 The system should be pressuretested once a year

ator's cooling fins

Fig. 154 Coolant condition can be checked with an inexpensive tester

1-42

GENERAL INFORMATION AND MAINTENANCE

Fig. 155 Check the condition of the radiator cap gasket and seal

Fig. 156 I sped coolant for contamination

LEVEL CHECK 1. Check the level on the see-through expansion tank.

CAUTION The radiator coolant is under pressure when hot. To avoid the i anger of physical harm, coolant level should be checked or replenish id only when the engine is cold. To remove the radiator cap when the engine is hot, first cover the cap with a thick rag, or wear a hef vy glove for protection. Press down on the cap slightly and slowly turn it counterclockwise until it reaches the first stop. Allow all the pr ssure to vent (indicated when the hissing sound stops). When the prt ssure is released, press down on the cap and continue to rotate it co) nterclockwise. Some radiator caps have a lever for venting the pre sure but you should still exercise extreme caution when removing tie cap. 2. Check the level and, if necessary, add coolant through the expans on tank to the proper level. Use a 50/50 mix of ethylene glycol anti-freeze and w ter. Alcohol or methanol base coolants are not recommended. Anti-freeze scj utions should be used, even in summer, to prevent rust and to take advantage t the solution's higher boiling point compared to plain water. This is imperathp on air conditioned trucks; the heater core can freeze if it isn't protected. Cooian should be added through the coolant recovery tank, not the radiator fille neck.

WARNING Never add large quantities of cold coolant to a hot engine! A cracked engine block may result! Each year the cooling system should be serviced as follows • Wash the radiator cap and filler neck with clean water. • Check the coolant for proper level and freeze protection. • Have the system pressure tested 15 psi. (103 kPa), If a replacemer) cap is installed, be sure that it conforms to the original specifications. • Tighten the hose clamps and inspect all hoses. Replace hoses that|are swollen, cracked or otherwise deteriorated. • Clean the frontal area of the radiator core and the air conditioning Condenser, if so equipped. DRAINING & FLUSHING

Fig. 157 Master cylinder fluid level

any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant Into a scalable container. Coolant should be reused unless it is contaminated or several years old. 1. Drain the existing anti-freeze and coolant. Open the radiator and engine drain petcocks (located near the bottom of the radiator and engine block, respectively), or disconnect the bottom radiator hose at the radiator outlet. 2. Close the petcock or reconnect the lower hose and fill the system with water—hot water if the system has just been run. 3. Add a can of quality radiator flush to the radiator or recovery tank, following any special instructions on the can. 4. Idle the engine as long as specified on the can of flush, or until the upper radiator hose gets hot. 5. Drain the system again. There should be quite a bit of scale and rust in the drained water. 6. Repeat this process until the drained water is mostly clear. 7. Close all petcocks and connect all hoses. 8. Flush the coolant recovery reservoir with water and leave empty. 9. Determine the capacity of your truck's cooling system (see Capacities specifications in this guide). Add a 50/50 mix of ethylene glycol anti-freeze and water to provide the desired protection. 10. Run the engine to operating temperature, then stop the engine and check for leaks. Check the coolant level and top up if necessary. 11. Check the protection level of your anti-freeze mix with an anti-freeze tester (a small, inexpensive syringe type device available at any auto parts store). The tester has five or six small colored balls inside, each of which signify a certain temperature rating. Insert the tester in the recovery tank and suck just enough coolant into the syringe to float as many individual balls as you can (without sucking in too much coolant and floating all the balls at once). A table supplied with the tester will explain how many floating balls equal protection down to a certain temperature (three floating balls might mean the coolant will protect your engine down to +5F (-15C), for example.

Brake Master Cylinder FLUID RECOMMENDATIONS I See Figure 157 Use only Heavy Duty Brake fluid meeting or exceeding DOT 3 standards.

The cooling system in you truck accumulates some internal rust and coirosion in its normal operation. A simple method of keeping the system clean is kn jwn as flushing the system. It is performed by circulating a can of radiator flush thiough the system, and then draining and refilling the system with the normal cool.int. Radiator flush is marketed by several different manufacturers, and is availal: le in cans at auto departments, parts stores, and many hardware stores. This operation should be performed every 30,000 miles (48,000 kmjor once a year.

CAUTION When draining the coolant, keep in mind that cats and dogs are attracted by ethylene glycol anti-freeze, and are quite likely to drink

LEVEL CHECK > See Figures 158 and 159 Chevrolet and GMC trucks are equipped with a dual braking system, allowing a vehicle to be brought to a safe stop in the event of failure in either front or rear brakes. The dual master cylinder has 2 entirely separate reservoirs, one connected to the front brakes and the other connected to the rear brakes. In the event of failure in either portion, the remaining part is not affected. Fluid level in the master cylinder should be checked on a regular basis. The master cylinder is mounted to the left side of the firewall.

GENERAL INFORMATION AND MAINTENANCE 1. Clean all of the dirt from around the cover of the master cylinder. 2. Be sure that the vehicle is resting on a level surface. 3. Carefully pry the clip from the top of the master cylinder to release the cover. On some later models, just pull up on the tabs. 4. The fluid level should be approximately V* in. (6mm) from the top of the master cylinder or at least above the WIN mark. If not, add fluid until the level is correct. Replacement fluid should be Delco Supreme No. 11, DOT 3, or its equivalent. It is normal for the fluid level to fall as the disc brake pads wear. If the fluid level in the master cylinder is excessively low, check the brake system for leaks and wear.

1-43

1. Clean all of the dirt from around the cover of the master cylinder. 2. Be sure that the vehicle is resting on a level surface. 3. Carefully remove the cover from the master cylinder. 4. The fluid level should be approximately V* in. (6mm) from the top of the master cylinder or at least above the MIN mark. If not, add fluid until the level is correct. Replacement fluid should be Delco Supreme No. 11, DOT 3, or its eguivalent. 5. Install the cover of the master cylinder.

Power Steering Pump

:â&#x20AC;˘-!: WARNING Brake fluid dissolves paint! It also absorbs moisture from the air. Never leave a container or the master cylinder uncovered any longer than necessary! 5. Install the cover of the master cylinder. On most models there is a rubber gasket under the cover, which fits into two slots on the cover. Be sure that this is seated properly. 6. Push the clip back into place and be sure that it seats in the groove on the top of the cover.

Clutch Master Cylinder FLUID RECOMMENDATIONS Use hydraulic clutch fluid or heavy duty brake fluid meeting DOT 3 standards.

FLUID RECOMMENDATION Use GM Power Steering fluid, or its equivalent. LEVEL CHECK > See Figures 160,161 and 162 Check the dipstick in the pump reservoir when the fluid is at operating temperature. The fluid should be between the HOT and COLD marks. If the fluid is at room temperature, the fluid should be between the ADD and COLD marks. The fluid does not require periodic changing. On systems with a remote reservoir, the level should be maintained approximately 1/2-1 in. (13-25mm) from the top with the wheels in the full left turn position.

Steering Gear FLUID RECOMMENDATIONS

LEVEL CHECK The clutch master cylinder is located on the firewall in the engine compartment.

Use GM Lubricant (part No. 1051052).

87981P39

Fig. 158 Remove the master cylinder cover

Fig. 159 Add brake fluid until the level is correct

Fig. 161 Hold the dipstick horizontally and check the power steering fluid level

87961P40

Fig. 160 Remove the power steering pump dipstick

Fig. 162 Add power steering fluid to the pump and fill it to the proper level

1-44 GENERAL INFORMATION AND MAINTENANCE 2. if the truck has been parked in temperatures below 20F (-7C) for any length of time, park it in a heated garage for an hour or so until the bail joints loosen up enough to accept the grease. 3. Depending on which front wheel you work on first, turn the wheel and tire outward, either full-lock right or full-lock left. You now have the ends of the upper and lower suspension control arms in front of you; the grease nipples are visible pointing up (top ball joint) and down (lower ball joint) through the end of each control arm. 4. If the nipples are not accessible enough, remove the wheel and tire. 5. Wipe all dirt and crud from the nipples or from around the plugs (if installed). If plugs are on the truck, remove them and install grease nipples in the holes (nipples are available in various thread sizes at most auto parts stores). 6. Using a hand operated, low pressure grease gun loaded with a quality chassis grease, grease the ball joint only until the rubber joint boot begins to swell out. The steering linkage should be greased at the same interval as the ball joints. Grease nipples are installed on the steering tie rod ends on most models. 7. Wipe all dirt and crud from around the nipples at each tie rod end. 8. Using a hand operated, low pressure grease gun loaded with a suitable chassis grease, grease the linkage until the old grease begins to squeeze out around the tie rod ends. 9. Wipe off the nipples and any excess grease. Also grease the nipples on the steering idler arms. Use chassis grease on the parking brake cable where it contacts the cable guides, levers and linkage. Apply a small amount of clean engine oil to the kickdown and shift linkage points at 7500 mile (12,000 km) intervals.

LEVEL CHECK No lubrication is needed for the life of the gear, except in the event oflpeal replacement or overhaul, when the gear should be refilled with a 13 oz. container of Steering Gear Lubricant (Part No. 1051052) which meets GM Specification GM 4673M, or its equivalent.

Chassis Greasing I See Figures 163,164,165,166 and 167 Refer to the diagrams for chassis points to be lubricated. Not all vehicles have all the fittings illustrated. Water resistant EP chassis lubricant (grease) conforming to GM specification 6031-M should be used for all chassis grease pants. Every year or 7500 miles (12,067 km) the front suspension ball joints;! both upper and lower on each side of the truck, must be greased. Most trucks covered in this guide should be equipped with grease nipples on the ball jo (its, although some may have plugs which must be removed and nipples fittaf

•••-•' WARNING Do not pump so much grease into the ball joint that excess gr ase squeezes out of the rubber boot. This destroys the watertight s al. 1. Raise up the front end of the truck and safely support it with jacks ids. Block the rear wheels and firmly apply the parking brake.

1 11 6

2 4

1. 2. 3. 4. 56. 7. 8. 9. 10. 11. 12. 13.

Air cleaner Control linkage Tie rod ends Wheel bearings Steering gear Master cylinder Transmission Carburetor linkage U-joints Driveshaft slip joints Drive axle Drag link Brake and clutch pedal springs 14. Transfer case 15. Throttle bell crank, 648L

10 i

Fig. 163 Lubrication points for the R-series

1. 2. 3 4. 5. 6. 7.

8. 9. 10. 11.

5 12 3

Air cleaner Control linkage Tie rod ends Wheel bearings Steering gear Master cylinder Transmission Carburetor linkage U-joints Driveshaft slip joints Drive axle

12. Drag link 13. Brake and clutch pedal springs 14. Transfer case 15. Throttle bellcrank, 64.8L 84901119

Fig. 164 Lubrication points for the V-series

GENERAL INFORMATION AND MAINTENANCE 1-45

1. Steering linkage 2. Wheel bearings 3. Air cleaner Transmission Dnveshaft slip joint Drive axle Clutch actuator Master cylinder Oil filter Steering gear 11. Engine

Fig. 165 Lubrication points for the C-series

Steering linkage Wheel bearings Air cleaner Transmission Rear Drive axle Transfer case Clutch actuator Master cylinder Front driveshaft Oil filter 11. Engine 12. Front drive axle

2 3. 4 5. 6. 7. 8 9 10.

Fig. 166 Lubrication points for the K-series

Body Lubrication and Maintenance LOCK CYLINDERS Apply graphite lubricant sparingly through the key slot. Insert the key and operate the lock several times to be sure that the lubricant is worked into the lock cylinder. HOOD LATCH & HINGES Clean the latch surfaces and apply clean engine oil to the latch pilot bolts and the spring anchor. Also lubricate the hood hinges with engine oil. Use a chassis grease to lubricate all the pivot points in the latch release mechanism. DOOR HINGES

Fig. 167 Front lubrication fittingsâ&#x20AC;&#x201D;C/K series

The gas tank filler door and truck doors should be wiped clean and lubricated with clean engine oil once a year. The door lock cylinders and latch mechanisms should be lubricated periodically with a few drops of graphite lock lubricant or a few shots of silicone spray.

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