Tomorrow's Tech, August 2014

■ PUMP 'N TANKS

■ DRILLED OR SLOTTED ROTORS?

■ CHRYSLER V6 SERVICE

August 2014 TomorrowsTechnician.com

CONTENTS

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REAL WORLD......................................12 Converting the Masses

Omar Trinidad and Ralph Tate, associate professors at Southern Illinois University, provide details on a gasoline-toelectric vehicle conversion on a 2001 Chrysler PT Cruiser.

Discover what they did to create a battery-powered electric vehicle.

12 ENGINE SERIES.................................16 Keeping the 3.5 Alive

If ever there was a service opportunity ripe for the taking, Chrysler’s 3.5L SOHC V6 engine (and its 2.7L, 3.2L and 4.0L cousins) is it. This engine was introduced back in 1993 as an “upgrade” from the earlier 3.3L pushrod V6 engine.

Find out what it takes to keep these engines running smooth.

16 UNDER COVER..................................36 The Hubbub on Undercar Noises Tech writer Gary Goms discusses how to diagnose noise, vibration and harshness (NVH) complaints in worn drivetrain components like universal joints, CV joints or wheel hub assemblies.

Also, we take a look at Slotted vs. Drilled rotors.

36 Babcox Blue

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Career Corner: Job Search Tips

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Finish Line: 2014 Ford/AAA Auto Skills

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HOME OFFICE 3550 Embassy Parkway Akron, Ohio 44333-8318 330-670-1234 FAX 330-670-0874 www.babcox.com

Service Advisor: Fuel System Service

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Under the Hood: A/C System Diagnostics

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Tech Tips Engine Compression Tests

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PRESIDENT Bill Babcox bbabcox@babcox.com 330-670-1234, ext. 217

TT Crossword

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SALES REPRESENTATIVES:

TT Classifieds

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Roberto Almenar ralmenar@babcox.com 330-670-1234, ext. 233

Report Card:

Jeep Dakar Concept Editor:

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EDITORIAL STAFF:

Managing Editor:

Coordinating Designer:

Publisher:

Advertising Services:

Subscriber Services:

Edward Sunkin, ext. 258 esunkin@babcox.com Tim Fritz, ext. 218 tfritz@babcox.com

Dan Brennan, ext. 283 dbrennan@babcox.com Jim Merle, ext. 280 jmerle@babcox.com

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Maryellen Smith, ext. 288 msmith@babcox.com

Tomorrow’s Technician (ISSN 1539-9532) (August 2014, Volume 13, Issue 5): Published eight times a year by Babcox Media, 3550 Embassy Parkway, Akron, OH 44333 U.S.A. Complimentary subscriptions are available to qualified students and educators located at NATEF-certified automotive training institutions. Paid subscriptions are available for all others. Contact us at (330) 670-1234 to speak to a subscription services representative or FAX us at (330) 670-5335.

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Bobbie Adams badams@babcox.com 330-670-1234, ext. 238 Doug Basford dbasford@babcox.com 330-670-1234, ext. 255 Don Hemming dhemming@babcox.com 330-670-1234, ext. 286 Sean Donohue sdonohue@babcox.com 330-670-1234, ext. 206 Jim Merle jmerle@babcox.com 330-670-1234, ext. 280 Glenn Warner gwarner@babcox.com 330-670-1234, ext. 212 John Zick jzick@babcox.com 805-845-1400 Fax-805 324-6015

What’s happening Airtex Fuel Delivery Systems Launches PUMP•ED Educational Program

RED KAP Joins School of the Year Sponsorship

Airtex Fuel Delivery Systems is introducing a new pilot program focused on educating future technicians in the automotive industry. The Airtex PUMP•ED program will train student technicians across the country in the areas of fuel system diagnostics and fuel pump installations.

Set to kick off in the fall of 2014, the Airtex PUMP•ED program will include selected technical schools and universities across the country.

Airtex will send its ASE certified technicians to classrooms to provide the most up-to-date information about today’s complex fuel systems. The technicians will show students the steps to make the right fuel system diagnosis, technical tips to avoid difficulty during repair work, and how to follow through to successful fuel pump installations.

As a part of the program, each technical school will receive training materials along with other valuable fuel system diagnostic and repair tool information.

In addition, students in the program will receive an official PUMP•ED performance pack that includes educational materials, tools and more.

For more information, visit: www.airtexproducts.com.

Red Kap, a manufacturer and distributor of comfortable, durable work-related clothing and outerwear, has joined WIX Filters in sponsoring two Babcox Media automotive excellence awards in 2014.

“Red Kap manufactures work apparel specific to the automotive market, making our brand the perfect addition to award programs recognizing workplace excellence in the aftermarket industry,” said Leslie Hunt, marketing manager for Red Kap. “We are proud to align the Red Kap brand with WIX Filters in support of those who represent the best in the industry.”

As part of the sponsorship, Red Kap will provide uniforms and merchandise to winners of the following awards: School of the Year – Open to all high schools or post-secondary schools that have a subscription to Tomorrow’s Tech magazine.

Red Kap will provide hats or shirts to the four finalists, as well as a uniform for every student of the winning school.

For more information, visit www.ttschooloftheyear.com.

Enter the 2015 Krazy Paint Pinstripers Design Contest!

Krazy Paint Pinstripers will create a design for the 49th annual Summit Racing Equipment I-X Piston Powered Auto-Rama Presented by RAD AIR Complete Car Care and Tire Centers.

The 2015 Krazy Paint Pinstripers Official Design Contest ends on October 20, 2014. Official Rules and more information is available at the event’s website at: www.ixpistonpoweredautorama.com under the Show Features tab.

Pinstripers will be able to submit any number of original entries on actual panels or digitally.

The three winners will be notified on October 31, 2014. The 1st place prize is $500, 2nd place prize is $250, 3rd place prize is $100.

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Fox Valley Technical College reported the expansion project at its J. J. Keller Transportation Center in Appleton, WI, was recently completed. For more on the school’s automotive and transportation program, visit: www.fvtc.edu/public.

Career Corner

10 TIPS TO IMPROVE JOB SEARCHES

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utoCare Career Hub knows how difficult and stressful job searches can be.

Sometimes, it feels like you’re just unable to burst through and make the best impression in the middle of a stressful job search, especially when you have so many other things on the front of your mind. Don’t let these things affect you, though!

Take our advice and eliminate little mistakes that have a huge impact on finding your next auto technician job. Everything from ineligible resumes to chatty interviews can ruin your chances at a job. Improve your chances with these handy tips.

By Libby Melhus http://autocarecareerhub.com

5. Being Too Hard On Yourself: Once again, negativity can seriously damper the job process. Put a positive spin on everything, and if you really don’t think that you’re good enough for the job, tell the recruiter that you no longer want to be considered. You can be assured that if you’re hard on yourself, the recruiter will be too.

6. Focusing On How Long and Difficult Your Job Search Has Been: Even if you’ve been on the hunt for years, you can still find a way to talk positively about the experience.

Focus on the great contacts you’ve made during that time, the training and knowledge you’ve been able to fine-tune, and the trends that you were able to keep up with.

1. Mediocre 7. Being Too Honest: It’s References Aren’t always tricky to answer Good References: Photo Courtesy of 3A Automotive, Phoenix, AZ the “tell me about your Surely everyone greatest weakness” question. Focus on how you corrected knows to stay away from bad references, but what about the weakness and overcame a challenge instead of the ones that are not good, but not bad? Those types of divulging too much about what’s wrong with you. references can look even worse to a recruiter. Don’t ask for a reference if you know that they won’t go the extra 8. Don’t Force Things: The job process takes a long mile for you. time. Things can drag on for a while, especially when 2. Negative Talk About Former Employers: Although there are many people involved with the hire. Don’t the phrase, “if you don’t have something nice to say, pester a company until they become annoyed with you.

Instead, close each meeting with a hiring manager by don’t say it at all,” still holds true, sometimes it speaks asking what you should expect next in terms of the hiring volumes to say something positive about a bad former situation. Yes, you were laid off, but what was the positive timeline. that came out of that situation? No job recruiter wants to 9. Don’t Talk Salary Too Soon: There’s a time to talk focus on the negatives. Neither should you. salary, and a time to prove that you’re worth the salary. If 3. A Bad Resume: A lot of people think that the more you focus early on in the interview process on your accomplishments and worth to the company instead of stuff they cram on their resume, the better it will be. what you want to make, it’ll be easier later on to have a That’s not going to help, especially if the job recruiter discussion about how much you expect to make. can’t read it. Never use a hard to read or small font and always check your spelling and grammar.

10. Applying to Jobs Blindly: You need to focus on job 4. Saying Too Much In An Interview: The interview is a openings that you have connections to, not jobs posted in a classified or general job site. Use niche websites, like conversation between two parties, not a speech given by AutoCareCareerHub, that already have a strong network you. Keep your talking to concise points, be inquisitive, for you to tap into. Then, use your already existing listen to what the recruiter says and end your responses network to find more job leads. ■ with a good question to further the conversation.

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edited by Tomorrow’s Tech staff Each month, Tomorrow’s Tech takes a look at some of the automotive-related student competitions taking place in this country, as well as the world. Throughout the year in “Finish Line,” we will highlight not only the programs and information on how schools can enter, but we’ll also profile some of the top competitors in those programs.

Because there are good students and instructors in these events, we feel it’s time to give these competitors the recognition they deserve.

Wisconsin Students Take Top Honors at National Ford/AAA Auto Skills Competition

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ustin Bublitz and Colt Morris from Grafton High School in Grafton, WI, have claimed the crown of America’s top student auto technicians at the annual Ford/AAA Student Auto Skills national competition.

The Wisconsin students, who registered the top score under the tutelage of instructor Carl Hader, outlast 98 others to claim their prize — and honors.

Students from across the country gathered in Dearborn June 10, to match wits and workmanship in a race against the clock – and one another – for the right to claim a National Championship and be named the top young automotive minds in America at the 65th annual Ford/AAA Student Auto Skills National Finals at Ford World Headquarters.

The competition, held on the grounds of Ford headquarters, began at 8:30 a.m., and when the dust settled nearly 90 minutes later, Bublitz and Morris drove their 2014 Ford Fusion into the

Photos courtesy Ford/AAA Student Auto Skills

Final Judging staging area with a completed “service repair” order.

Taking the Field With more than $10 million dollars in scholarship prizes in the balance, state winners gathered in Dearborn to solve “real world” automotive challenges – both digital and mechanical – in a timed competition.

A quick mind and steady hands were required as top auto students worked with wrenches and computers alike.

With automotive sales up across the board, and new and innovative technologies becoming a bigger part of the manufacturing

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process, the Ford/AAA Student Auto Skills competition is shaping the next generation of auto technicians who will work on these vehicles.

Beginning with a shotgun start, the student competitors (all paired in two-person teams) raced to their vehicles to review a work order that challenged them to diagnose and repair a number of purposefully placed “bugs” ranging from digital to mechanical and electrical.

Once the repairs were completed, it was a race to shut the hood, fire up the engine and steer the vehicle across the finish line – where a scrutinizing judging team awaited.

To earn the National Title, Bublitz and Morris earned a “perfect car” score by flawlessly repairing all the “bugs” without any demerits. Students are graded on quality repair workmanship and safety. Combined with the results of a written examination taken on June 9, their score allowed them to hoist the trophy as national champions.

‘Extra Credit’ In addition to scholarships, the National Champion Wisconsin team enjoyed an immersive, weeklong job shadow experience with

2011 Daytona 500 winner Trevor Bayne and his Wood Brothers Racing team, and the No. 21 Motorcraft/Quick Lane Ford Fusion car at the Coke Zero 400 in Daytona Beach, FL, – the famous site of Bayne’s spectacular win at age 20.

Ford/AAA 2014 Top 10 Finishers 1. Wisconsin 2. Oklahoma 3. Maine 4. Oregon 5. Hawaii 6. Massachusetts 7. Rhode Island 8. Iowa 9. Kansas 10. Nevada

“For today’s automotive technicians, being able to diagnose and repair a computer-related malfunction is just as critical as fixing mechanical failures,” said Marshall L. Doney, AAA Chief Operating Officer.

“As a generation that has grown up with digital technology, this

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year’s students are uniquely qualified to lead the auto industry forward and you saw their brilliance on display today in a high-octane atmosphere matching the nation’s best talent from coast-to-coast.”

“The automotive technicians of tomorrow must be well-educated and highly-skilled to meet the current and future technological advances in automotive technology,” said Steve DeAngelis, Ford’s Manager of Technical Support Operations.

“The people at Ford are committed to training and retaining the best technicians in the industry, which is why we are so proud of our continued involvement in the Ford/AAA Student Auto Skills competition, which invests in our highlyskilled technicians of tomorrow.”

For additional information on the competition, visit: autoskills.aaa.com.

Do you have an outstanding student or a group of students that needs to be recognized for an automotive-related academic achievement?

E-mail us at esunkin@babcox.com.

Real World

CONVERTING THE MASSES

By Omar Trinidad, Assistant Professor, Automotive Technology, and Ralph Tate, Associate Professor, Southern Illinois University

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he electric vehicle’s (EV) popularity among consumers is rising due to its zero emissions, increased efficiency and lower operating costs.

While some will choose to purchase a new EV, there has been a growing group of enthusiasts who would rather convert or have someone else switch their petroleum-burning vehicles into electric drive.

So why convert a vehicle? It all boils down to cost. This article will cover a conversion performed on a 2001 Chrysler PT Cruiser (EV Cruiser) with a total conversion cost of about $12,000. This might seem like a high price to pay, but with a daily operating cost of 50 cents per day, it’s easy to see how the cost can be recoverable. One main item that prevents consumers from moving toward an EV is the fear of an expensive battery. Although the batteries in the EV Cruiser are rated to last about eight to 10 years, with the way the EV Cruiser has been driven, the battery cost of $5,500 should be recovered after five years of use. It took about one year to finish our project, which included six months of waiting for the batteries to arrive.

The choice between buying and converting is based on finances, fabrication skills, desired range and comfort amenities. Increasing the desired range and comfort level of the vehicle will drastically increase an EV purchase or project cost. For example, the $87,400 Tesla Model S rated to go 275 EPA-certified miles on a single charge comes with all the creature comforts of a luxury vehicle — including a 17” touchscreen infotainment system. On the other side of the spectrum is the Mitsubishi i-MiEV. For $29,000 this vehicle will drive for 62 miles on a single charge, but the comfort level is similar to a base model sub-compact.

Conversion Phases: Design Converting a vehicle into an EV can be categorized into three phases: design, teardown and assembly, and testing.

Designing the vehicle starts with specifying the type of system desired, amount of range and the types of accessories desired. Thoroughness and specificity is key when designing.

It is the most challenging and time-consuming phase, but having a robust plan of action will prevent any waste of time or finances.

Fortunately, EV conversions are not new and there are numerous credible resources on the web that have chronicled EV conversions on various types of vehicles. The EV community is a very tightknit and helpful group of people who are willing to share information and assist with any type of EV project. Having this type of resource and support allows for a thorough design and a successful conversion.

The EV Cruiser was designed with three goals: to attain 35

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miles of range, a top speed of 70 mph, and to cause minimal alterations to the vehicle. During the design phase, the first step was to choose between an alternating current (AC) or a direct current (DC) powertrain system. The price between the two systems can vary as much $3,000 to $6,000 depending on the type of motor and controller. Just like most purchases, all of the major components on an EV project will increase in price as efficiency increases. AC conversion kits cost more, but they are also more efficient and can be programed to enable regenerative braking. On the contrary, DC conversion kits cost less, but are less efficient

Figure 1

Figure 2 and are unable to utilize regenerative braking. To keep costs low, the EV Cruiser was designed with a DC Logisystems WarP-Core controller rated at 750 amps Figure 3 and a 9” Netgain WarP series wound DC motor rated at 34 horsepower at 144 volts, and 100 lbs.-ft. at 500 amps (see Figure 1). The motor is equipped with carbon brushes, which are designed to withstand about 50,000 miles of use.

Part of the design phase was specifying battery types and mounting locations. The two main choices of batteries were conventional 12-volt lead acid batteries and lithium-based batteries. Lead acid batteries are more affordable, but are significantly heavier compared to the more powerful lithiumbased batteries. In order to increase range by decreasing weight, the EV Cruiser utilizes 38 prismatic-type cells of lithium iron phosphate (LiFePO4). Each cell is wired in series to provide 120 nominal volts (see Figure 2). To charge the LiFePO4 batteries, an Elcon PFC1500 charger rated at 1.5kW was mounted in the engine bay (Figure 1). It is designed to charge using a 1.5kW Level-1 charger directly from a regular 120V AC outlet, or a 3kW Level-2 charger similar to a 240V AC dryer outlet (see Figure 3).

Part of the lithium batteries’ cost comes from the BMS (battery management system), which protects it from failing due to heat and over-charging. The BMS in Figure 4 illustrates how each cell is monitored and managed to maintain a certain temperature and voltage. In addition to the BMS, a relayed system with a shunt resistor must be used

to precharge the system before fully connecting both sides of the battery to the controller. Similar to the three system main relays on the Toyota Prius and other hybrids, the BMS protects the controller from the high-voltage shock of the batteries, though unlike the Toyota Prius, the EV Cruiser is designed with two contactors wired in series (see Figure 5).

Based on the design of the vehicle, the batteries are either stored in place of the gas tank, inside the newly gutted and spacious engine compartment, or beneath the passenger seats (Figure 2). On trucks however, the battery boxes can be designed to fit beneath the truck bed to allow utilization.

Some opt to place the battery box where the spare tire was stored. No matter where the batteries will be stored, it’s important to keep in mind that the EV utilizes a high-voltage DC system and that the batteries can produce a flammable gas when charging. Thus, safety must always trump range or aesthetics.

One of the main goals of this project was to keep alteration and cost of the vehicle to a minimum. The amount of accessories was kept to a minimum by removing the power steering system, and the heating and air conditioning functions (HVAC). Similar to most projects, funding will be the main variable that will increase or decrease the inverse correlation between range and comfort. The main drawback to a minimalistic vehicle is a less “normal” driving experience.

Figure 5

It is possible, depending on the design of the electric motor and drivetrain, to utilize the other side of the motor shaft to drive an accessory pulley. This pulley can provide torque to the power steering pump, AC compressor and alternator. The main drawback to this system is the amount of energy it will drain from the battery to power the accessories. Some vehicles do not allow for this system, but an electric power steering pump and AC compressor can provide the pressure to keep the original systems functional.

Figure 4 TomorrowsTechnician.com 13

Figure 6 One of the main disadvantages of an EV, regardless of whether the vehicle is a conversion or not, is the amount of energy the HVAC system draws from the batteries. The amount is second only to the motor and controller. For example, Mitsubishi’s iMiEV is designed with a 47kW motor and an HVAC system with a combined max power rating of 9.5kW, which makes it one of the most conservatively produced EVs. There are two heating system types available for EV conversions: the first utilizes a ceramic heater that replaces the heater core, the second is a heating system that can be plumbed to the heater core to utilize the existing plumbing system.

Even though the utilization of the HVAC system will be based on location and desired comfort, it is still essential to have a 12-volt system and a vacuum pump for the brake booster. The 12-volt system can be maintained by a DC-to-DC converter or an alternator. The vacuum pump system must be designed with a pressure sensor to stop the pump at about 21 inHg. These pumps can be purchased from an automotive manufacturer that utilizes vacuum pumps on some of their vehicles or from an EV conversion vendor.

Although the transmission is not considered an accessory, it is another component in which a decision between range and comfort has to be taken. Based on the desired top speed and drivetrain configuration, torque from the motor can be directly

applied to the rear differential or transmission for a rear-wheel-drive vehicle, or through a transaxle on a front-wheel-drive system. Utilizing an automatic transmission will require having a programmable controller to program the shift points, a fabricated coupler to transfer torque to the input shaft of the transmission, and an auxiliary transmission fluid pump to sustain fluid pressures while the motor is not spinning at idle.

The EV Cruiser utilizes the original manual transmission without a clutch to minimize alterations to the vehicle, keep costs low and to increase range.

For optimum speed, the transmission is initially shifted into second gear then to third for more speed. Shifting without the clutch may take some time to get used to, but when timed properly, the synchronizers allow for smooth upshifts.

Teardown & Assembly Once the desired system and range are specified, the teardown and assembly phase starts. This phase begins by removing the internal combustion engine (ICE), emissions, exhaust, fuel and cooling system components. Furthermore, based on the desired accessories, other components such as the HVAC components would need to be removed to reduce weight.

One of the main tasks for this phase is fabricating the battery boxes, adapter plate, motor mounts and coupler. The battery boxes on the EV Continues on page 52

Engine Series

Adapted from Larry Carley’s article in

KEEPING THE 3.5 ALIVE

Service Notes for Chrysler’s V6 Engine Built from 1993-2010

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f ever there was a service opportunity ripe for the taking, Chrysler’s 3.5L SOHC V6 engine (and its 2.7L, 3.2L and 4.0L cousins) is it. This engine was introduced back in 1993 as an “upgrade” from the earlier 3.3L pushrod V6 engine. Some would question whether the move was a step forward or backward because the 3.5L V6 (and its variants) has a poor reputation for reliability. Lubrication issues, oil sludging, coolant leaks, overheating and low-mileage engine failures have plagued this engine family from the get-go.

Some blame the design of the engine itself for all the ills it has suffered, while others blame consumers for not maintaining their engines properly. But regardless of who’s at fault, these engines do represent a significant service opportunity.

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Engine Details The new 3.5L engine used essentially the same cast iron block and crankshaft as the 3.3L (same 81 mm stroke), but the bore size was increased from 93 to 96 mm and the compression ratio was bumped up to 10.4:1.

The 3.5L engine is an even-firing power plant with aluminum cylinder heads, a single camshaft in each cylinder head and four valves per cylinder. It has a sequential fuel injection system with distributorless ignition. The engine is rated from 214 to 220 horsepower depending on the model year, and delivers good torque from 2,000 to 5,600 rpm.

versions of the 3.5L SOHC V6 were used in a wide range of Chrysler models including the 300 and 300M, Avenger, Challenger, Charger, Concorde, Intrepid, Pacifica, Prowler and Sebring.

The last 3.5L V6s were produced in 2010. For model year 2011, the engine was replaced with a totally new 3.6L DOHC Pentastar V6.

Coolant Leaks

Chrysler designed new heads and manifolds to accommodate the overhead cams, and a sexy dual-throttle cross ram intake system with a manifold tuning valve.

The front of the block was modified to accommodate a frontmount oil pump and a timing belt drive for the overhead cams. The water pump was built into the front cover so it could be driven by the timing belt.

The pistons are cast aluminum with full floating wrist pins, ductile iron compression rings, and are relived so the engine will freewheel without valve interference if the timing belt breaks.

Under the Hoods The 3.5L V6 was used in 1993-’97 Chrysler LH cars (Dodge Intrepid, Chrysler New Yorker and LHS, Eagle Vision) and the ’97 Plymouth Prowler.

In 1998, the 3.5L was reworked and given an aluminum block and additional tweaks to increase the power to 253 to 255 hp, depending on the application. Unfortunately, Chrysler failed to upgrade some things that needed to be upgraded, like the undersized oil galley passages in the block, the troublesome coolant pipe that runs under the intake manifold, the undersized PCV system that doesn’t pull enough air through the crankcase and the overall reliability of the engine itself.

The 1998 to 2010 all-aluminum

Any engine can develop coolant leaks after years of service, and the 3.5L V6 is no exception. These engines have a small metal heater tube that runs from the front of the engine under the intake manifold. There’s an O-ring seal at the front of the engine that tends to fail and leak after so many years of service. The metal tube can also rust from the inside out and leak coolant. Replacing this tube is a labor-intensive and time-consuming repair job, as it requires removing the upper intake manifold and fuel injector rail.

The replacement O-ring is P/N 06505692AA, and the metal tube is P/N 04792185AC. Replace both at the same time to prevent further trouble down the road.

The cooling system on the 3.5L uses a water pump with a molded plastic impeller. The design is more efficient than a typical stamped metal impeller and produces less cavitation, but the soft plastic impeller can be eroded and worn down by rust and sediment in the coolant. If this happens, the pump won’t circulate as much coolant, causing the engine to run hot and overheat.

If an engine is running hot and there are no obvious external coolant leaks, and the radiator cooling fans are cycling on and off, and the radiator isn’t clogged or obstructed, pressure test the cooling system to check for an internal coolant leak. Leaky head gaskets are also a common problem on these engines.

If the cooling system holds pressure, and the cooling fans are functioning normally, but the engine is running hotter than normal, it’s probably a worn water pump.

If you do change the water pump, change the thermostat too. One other possibility would be a restricted catalytic converter that’s creating backpressure and causing heat to remain in the engine.

Regular coolant maintenance is absolutely essential on these engines, so if the coolant has not been changed in five years, it may be time to drain, flush and refill the cooling system. Using a coolant exchange machine will make it easier to keep air out of the system.

For 2001 and newer vehicles, Chrysler recommends a long-life HOAT (Hybrid Organic Acid Technology) or GO-5 type of antifreeze that meets its MS9769 requirements.

HOAT coolants contain a combination of inorganic acid and organic additives for added protection against aluminum corrosion, which is important with the allaluminum 3.5L engines. The same coolant can be used in the older 1993-2000 applications instead of a conventional green formula coolant.

If you’re replacing a water pump, be sure to inspect the upper and lower radiator hoses, and heater hoses.

Replace any hose that is not in perfect condition. If the hoses are more than 10 years old, replace all of them.

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On 2006-’08 Dodge Charger and Magnum and Chrysler 300 vehicles, Chrysler issued a recall (L08110617-010) regarding a fan separation problem.

It only applies to cars equipped with the severe-duty cooling package. The free fix involves replacing both fans with new ones (P/N CBHZL080AA) that hopefully won’t come apart and damage the radiator.

Oil Sludging Problem One of the most common problems with these engines is that the oil tends to sludge and break down — especially if the oil is not changed every 3,000 miles. These engines run hot, and with a PCV

The oil pan on the 3.5L is made of Antiphon steel, which consists of a layer of rubber sandwiched between two layers of steel. This deadens sound transmission and helps reduce noise. Fill capacity is 5 quarts when changing the oil. system that barely flows enough air to pull moisture out of the crankcase, it doesn’t take long to create an oil sludging problem.

As sludge and varnish build up inside the engine, it can restrict the small oil passages that deliver oil to the crankshaft bearings, increasing the risk of oil starvation and bearing failure. Many of these engines have failed at relatively low mileages (less than 80,000 miles) because of spun bearings and/or broken connecting rods.

If you have a customer who drives a Chrysler product with a 3.5L V6 (or a 2.7L, 3.3L or 4.0L), you need to stress the importance of frequent oil changes (every 3,000 miles, not the 7,500-mile intervals recommended by Chrysler).

If you find evidence of maintenance neglect such as foaming or sludge on the underside of the oil filler cap, a plugged PCV system or oil that looks like tar when it drains out of the crankcase, recommend a crankcase flush to remove as much of the accumulated sludge and varnish as possible when the oil is changed.

Also, inspect and clean the PCV valve when the oil is changed, and replace the PCV valve every 30,000 miles to keep the PCV system working at peak efficiency.

Note: Chrysler technical service bulletin (09-01-96) describes a hydraulic lash adjuster noise problem with this engine. A heavy clicking or ticking noise coming from the top of the engine that changes with rpm may occur due to oil aeration if the crankcase is overfilled with oil. If the noise persists after correcting the oil level, it may indicate valvetrain damage.

The engine is even-firing, with a firing order of 1-2-3-4-5-6. Cylinder #1 is at the right front, with #1, #3 and #5 on the right bank and #2, #4 and #6 on the left bank.

Don’t Forget the Timing Belt Chrysler probably should have used a timing chain in this engine, but instead opted for a less expensive timing belt. The factory recommended replacement interval for the belt is 100,000 miles.

The early 1993-’97 3.5L engines are non-interference

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engines, so if the timing belt snaps or jumps time, the engine won’t bend any valves. The all-aluminum 19982010 engines, however, are interference engines. If the timing belt is not replaced at the recommended mileage, the risk of belt failure increases with every mile that’s driven. If the belt breaks, the vehicle owner will be looking at a very expensive repair. On older cars, the cost of the engine repairs will be more than the car is worth.

Replacing a timing belt on a 3.5L V6 is typically a two- to three-hour job, so the cost of preventive maintenance is relatively cheap compared to what a broken timing belt could cost the vehicle owner.

The life of the water pump is about the same as the timing belt, so if you’re replacing one, you should replace both at the same time.

Other Preventive Maintenance The newer 3.5L V6s came factory-equipped with longlife platinum resistor spark plugs with a recommended replacement interval of 100,000 miles. The first generation 1993-’97 engines have conventional 60,000-mile plugs. Replace them with same or better and gap to 0.048” to 0.053” on the ’98-and-newer engines, and 0.035” on the ’93 to ’97 engines.

The second generation 1998-and-newer 3.5L engines have a coil-on-plug ignition system, so you obviously have to remove the coils before you change

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the plugs.

Be sure to inspect the long tube on each coil that fits down over the spark plugs for cracks or carbon tracking. Replace as needed to prevent misfires.

Caution: Chrysler TSB 18-02401 warns against cranking the engine with any of the coils removed. If any of the coil circuits shorts to ground in the engine bay, you can damage the coil driver circuits in the PCM! Also, if you notice oil residue on any of the spark plugs, the spark plug tubes in the valve cover and the valve cover gasket might be leaking. Replace them as needed.

On the first-generation engines with a distributorless ignition system, be sure to inspect the spark plug wires when changing the plugs. The original suppression wires on a high-mileage engine will likely need to be replaced.

Be careful when changing the spark plug wires. The wires run under the fuel rail on the left side of the engine. There should be enough clearance to run the wires under the fuel rail without having to remove it. Don’t attempt to bend or force the fuel rail upward for added clearance as doing so may damage the rail. Also, change one wire at a time so you don’t mix up the firing order.

The older 3.5L V6 engines have two drive belts, a poly V-belt (flat belt) for the alternator and power steering pump, and a conventional V-belt for the A/C compressor. So unlike the newer 3.5L engines that use a serpentine belt with an automatic tensioner, tension on both belts needs to be checked and adjusted periodically. Each belt has its own separate tensioner pulley.

Chrysler recommends adjusting the belts on the older engines every

15,000 miles. Use a belt gauge to check and adjust the tension.

For the flat poly V-belt, set the tension to 190 lbs. (new) or 160 lbs. (used). For the A/C compressor V-belt, set the tension to 160 lbs. (new) or 120 lbs. (used).

Miscellaneous Fixes If you encounter a 2008 Chrysler 300, Magnum or Charger with a MIL light on and a DTC P050D (cold start rough idle set), the PCM may need to be reflashed with updated programming to eliminate the false code. Refer to Chrysler TSB 18-031-08 for details.

On some 2008 and 2009 Chrysler 300, Magnum and Charger models with the 3.5L V6, a strange whistling noise may be heard in the engine compartment

while the engine is running. It could be a vacuum leak, but it could also be a noisy purge control solenoid. Chrysler TSB 18-03608 says the fix for this is to reprogram the PCM with updated software that corrects the condition.

On 2009-’10 Dodge Challengers and 2008-’10 Chrysler 300, Magnum and Charger cars, the MIL may come on because of a false DTC P0339 code (crankshaft position sensor intermittent set). The fix is not to replace the crank sensor, but to reprogram the PCM with a software update (TSB 18-005-11).

If the code persists after the software update, it may be necessary to shim the crank sensor or replace the crankshaft flex plate. ■

Service Advisor

Adapted from Andrew Markel’s article in

A CLEAN FUEL TANK Improves A Fuel Pump's Diet

F

uel pump replacement comebacks can be costly and can hurt your reputation.

One of the leading causes of failure is the tank. If a vehicle gets 20 miles to the gallon, then more than 5,000 gallons of gas (from many stations) will go through the tank in 100,000 miles. And during this time, sediment, rust and debris from the pump can find its way into the tank.

Capturing Contaminates Removing all contaminates is critical. If possible, have the tank steam-cleaned at a radiator shop

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August 2014 | TomorrowsTechnician.com

that performs these services. They can recondition a tank and check for leaks that you may not be able to spot. Your goal in cleaning the tank is to restore the environment inside the tank to the same state it was in when they put fuel in before it drove off the assembly line.

If you think the new sock or strainer on the full pump will catch all of the bad stuff, you are wrong. The typical sock or strainer is designed to catch contaminates that are between 50-100 microns in diameter. Forty microns is the size of a human hair. A typical inline fuel filter can catch particles as small as 10 microns.

The sock also has a limited capacity due to its

small surface area.

Always install a new filter. Sounds simple, but it is often forgotten. The old filter can restrict flow and make the new pump work harder. This makes for a hotter running pump that fails sooner.

When Fuel Cab Become a Contaminate Although cases involving contaminated gasoline are relatively rare nowadays, they still occur. In many cases, the technician has replaced the fuel pump or mass air flow (MAF) sensor to address a P0171/P0174 “lean-condition” DTC with no result.

In all likelihood, the technician didn’t consider the possibility that the vehicle’s fuel might be contaminated with E85 gasoline, diesel fuel, stale gasoline, or, to a lesser degree, sugar and water. The fact is that the first three fuel contaminants tend to lean out the air/fuel mixtures, while sugar and water generally cause intermittent cranking, no-start and stalling complaints. In total, and depending upon the percentage present in the fuel tank, contaminated fuel can mimic the symptoms produced by defective fuel pumps, fuel injectors and fuel control components like MAF sensors.

E85 Gasoline Although it’s hard to think of E85 gasoline as a fuel contaminant, it’s important to remember that E85 is designed for use only in flex-fuel vehicles. Because pure ethanol requires approximately 150% more volume to support stoichiometric combustion than does pure gasoline, some early flex-fuel vehicles use an ethanol sensor in the fuel line to estimate the volume of ethanol in the fuel.

Later flex-fuel vehicles simply use data inputs from

30 August 2014 | TomorrowsTechnician.com

their air/fuel ratio sensors to adjust fuel injector pulse width to accommodate increased volumes of ethanol.

Most flex-fuel vehicles can be identified by an exterior flex-fuel emblem and, in many cases, a yellow gas cap.

Many motorists inadvertently top off their fuel with E85 because they are unaware that E85 gas pump nozzles are generally equipped with yellow covers.

Immediately afterward, they begin experiencing leanfuel driveability symptoms such as hard starting and loss of power accompanied by a P0171 or P0174 DTC, depending upon the application.

At this point, let’s note that “ethanol” and “methanol” are distinctly different alcohol compounds. Methanol is used in racing applications because its high latent heat of vaporization keeps the engine cool, and because it produces slightly more horsepower than

gasoline.

But, even with those advantages, methanol has a major tendency to corrode metal surfaces and degrade fuel hoses, O-rings and other soft fuel system components.

Additional Fuel System Diagnostics and Service Bad grounds and connections can kill a new pump.

Check the connector for any signs of thermal damage that may indicate there was a voltage drop or a circuit

with high resistance. Do not assume the old pump caused the thermal damage. Bad grounds and circuits will stay with the vehicle and damage the new pump.

Filter the fuel before you put it back in the tank. If a fuel pump went through a full meltdown, chances are the pieces from the old pump are still in the removed fuel. Filter the fuel before it goes back in the tank. Many fuel caddies have built-in filters.

Check the EVAP system before returning the car to the customer. It takes at least one drive cycle for most vehicles to set an EVAP code. A leak due to disturbing the lines may not set a code during the initial test drive. The code may come on after the vehicle has been sitting for a while or a certain temperature has been reached.

Check the system with a scan tool and/or smoke machine before delivering the car to the customer. Some scan tools and vehicles can perform a self-leak check. Fuel filler necks are especially susceptible to leaks if the tank has been dropped.

In the Rust Belt states, corrosion on the top of the tanks and on the fuel lines is starting to become a big headache during fuel pump replacement. This is due to brines being used on roads to prevent icing. Brines stick to vehicles — even the tops of fuel tanks — long after the snow storms have passed and even into summer.

Then, every time it rains, the brines are reactivated and start to corrode the tank.

Also, check the straps and mounting hardware

32 August 2014 | TomorrowsTechnician.com

of the tank. In 2010, Ford recalled 1.2 million trucks due to corrosion of the straps that held in the gas tank.

Note: It’s a good practice to inspect the fuel lines for corrosion before starting the job. Nothing is worse than having to call the customer because a line collapsed due to corrosion during removal or installation.

Fuel Tank Cleaning Procedures 1. Once the tank has been removed, drain all fuel from the tank. Use only an approved container or a fuel caddy to filter and store the fuel.

2. Clean accumulated road debris or rust from the top of the fuel tank, especially around the module or hanger assembly to avoid contaminating the fuel tank.

3. Remove the lock ring.

4. Remove the module or hanger assembly.

5. Clean and flush the tank with water before installing the new module or hanger assembly.

6. Swish the fuel tank around in a circular motion to collect any debris remaining in the fuel tank.

7. Slowly and carefully poor the fuel out of the tank into the approved container or fuel caddy.

8. Turn the fuel tank over, then tap the bottom to remove any debris.

9. Clean the inside of fuel tank with dish soap and water. Modern fuel tanks are difficult to clean because of their internal baffling.

If a tank can be cleaned, it’s important to use highpressure soap and water to remove the dirt. The tank

34 August 2014 | TomorrowsTechnician.com

should then be thoroughly dried by circulating air through the tank or by simply placing it in the summer sun. In many cases, a fuel tank replacement is the most cost-effective and safe alternative.

10. If possible, take a lint-free shop towel and wipe the inside of the fuel tank until it is clean.

11. Dry out the fuel tank completely with compressed air.

12. Inspect the fuel tank carefully. If the tank is rusted inside or shows signs of physical damage, it must be repaired or replaced.

13. After the tank has been dried with compressed air, let it sit for 30 minutes. â–

UnderCover

WHAT’S ALL THE HUBBUB ON UNDERCAR NOISES? Adapted from Gary Goms’ article in

Diagnosing NVH Complaints in Drivetrain Components

T

hanks to advanced technology, modern vehicles operate with fewer noise, vibration and harshness (NVH) complaints than ever before.

Consequently, when a noise, vibration or harshness issue arises, it’s most likely to be caused by worn drivetrain components like universal joints, constant velocity (CV) joints or wheel bearing hub assemblies. In any Photo 1: Couplers are designed to operate at minimal angles of case, NVH complaints deflection and to dampen drivetrain noises. can often be the most challenging to diagnose when a tech or service writer can’t duplicate the cars. While some low-angle joints are made with exact driving conditions under which they occur. a rubber-compounded material, most modern If the noise can’t be duplicated and verified on universal joints are made of a steel cross connecting four trunnions containing lubricated a test drive, it’s doubly important for the service needle bearings. writer to determine during the customer See Photo 1. interview when and how the particular NVH Eventually, the needle bearings wear grooves complaint occurs. into the case-hardened surfaces of the cross, Remember also that some wheel bearing which allows the propeller shaft to rotate slightnoises are transmitted through different parts of ly off-center. The rule-of-thumb spec for offthe chassis. To reduce diagnostic errors, verify center rotation is generally 0.010” measured at noises by using chassis-mounted sound the end of the propeller shaft tube. In the most detectors or by thoroughly inspecting all catastrophic cases, the lubricant in the trunnion components while the vehicle is on the lift. bearings can be lost, which will cause the joint Joint Work to eventually separate.

In modern automotive architecture, universal Larger universal joints can be inspected for joints are most commonly found on the rear extreme wear by twisting the propeller shaft axles of light trucks, SUVs and RWD passenger back and forth.

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Photo 2: While a noise from a bad propeller shaft support bearing might sound like a bad wheel bearing, it will resonate at approximately three times wheel speed.

Smaller joints can be tested by prying the trunnions back and forth with a large screwdriver.

Preventive inspections can be made by watching for rust formations around the trunnion seal indicating that the trunnion has lost its lubrication. In another case, the driver might complain of a snapping or popping sound at low speed, which might indicate that the trunnions are seizing due to lack of lubrication. Seizing can be diagnosed only by removing the propeller shaft and checking each universal joint for smooth operation by hand.

See Photo 2.

Because the trunnion bearings are located at 90-degree intervals, a conventional universal joint actually accelerates and decelerates as it turns.

To eliminate this uneven rotating speed, universal joints are installed in pairs and phased along the same plane on the propeller shaft.

When the U-joints are correctly phased, the propeller shaft speed smooths out because one U-joint

accelerates as its companion joint decelerates. Unfortunately, some splined two-piece truck propeller shafts can be incorrectly phased during reassembly. This condition can be difficult to detect since incorrect phasing often results in a harmonic vibration that resonates under different conditions of speed and load.

For this reason, it’s always important to index the propeller shaft to its mating flanges and to its individual parts before replacing universal joints.

Harmonic vibrations can also be caused by universal joints operating at unequal angles of deflection at the propeller shaft.

These angles should be measured with the vehicle at normal suspension height and load. In some applications, the angle at the rear axle can be adjusted, either with shims or by a control arm eccentric, to allow the rear axle pinion gear shaft to operate in the same plane as the transmission or transfer case output shaft.

See Photo 3.

Photo 3: Because this is an independent suspension system, the angle of deflection between the pinion gear and propeller shaft is nearly zero.

Although some U-joints are serviced as a unit with the propeller shaft, most can be replaced. Using a hand-held universal joint press will prevent damage to the propeller shaft, as will soaking the joint in penetrating oil before removal. If required, pack the needle bearings with chassis grease and always lubricate the propeller shaft loops before assembly. If used, grease zerks should point toward the propeller shaft and be aligned along the same plane. If the Ujoint feels too stiff after it has been installed, align the trunnions by tapping the propeller shaft loops with a medium-sized hammer.

Several basic rules should cover CV half-shaft installations. First, make it a habit to remove only one shaft at a time because there still are a few vehicles in which the differential carrier can drop to the bottom of the gear case when both axles are removed at the same time. Next, avoid mixing the right- and lefthand shafts because some minor differences might exist between their compression or extension lengths.

Because using an impact wrench can damage the joint or adversely affect wheel bearing preload, always use a torque wrench to tighten the CV axle retaining nut to specification.

Constant Velocity Joints

Hubs and Bearings

CV joints have made life much easier for techs because, as the name implies, CV joints operate at a more constant speed than do conventional universal joints. They do, however, tend to operate more smoothly when the right and left axle shafts are operating at equal angles of deflection.

The most common CV joint failures are caused by a loss of lubricant through a torn or perforated CV boot. The symptom of a leaking CV boot is a lubricant “spray” collecting on the chassis surfaces surrounding the joint. When the lubricant is completely gone, the joint will wear out and eventually separate.

The most common symptom of worn CV joints is the clicking noise that characteristically occurs when the vehicle is driven through a short right- or left-hand turning radius under power. On rare occasion, a CV joint will seize, which causes a wobbling sensation in the steering wheel. A potential catastrophic failure might be indicated when the transmission engagement between drive and reverse is accompanied by a clanking or knocking noise.

Because tapered-roller front wheel bearings require frequent lubrication and adjustments, permanently preloaded and lubricated bearing hub assemblies have generally replaced them. Correct preloading is required in modern wheel bearing assemblies because the clearance between wheel speed sensors and tone rings is critical. Preloaded bearings also reduce the rotating friction of the disc brake assemblies by helping maintain a small, but significant, air gap between the brake rotor and pads.

When diagnosing any wheel bearing noise, it’s important to remember that modern wheel bearings must: 1) Support the vertical load created by the vehicle’s weight, 2) Withstand the forward thrust of the driving wheels, and 3) Resist lateral loading during cornering.

Any noise coming from the wheel bearings will, therefore, be most often duplicated under one or more of these driving conditions.

40 August 2014 | TomorrowsTechnician.com

When road-testing the vehicle to duplicate an NVH complaint, notice that wheel bearing and drivetrain noises are constant, whereas tire noises vary according to the road surface.

See Photo 4.

If a vacant parking lot is available, weave the vehicle back and forth at low speed to alternately

load and unload the wheel bearings.

Notice also if the noise level changes as the vehicle stops and accelerates.

After the wheel bearings have warmed up after an extended drive, check each bearing hub’s temperature with an infrared heat gun. In most cases, the defective

wheel bearing will indicate a higher operating temperature.

See Photo 5.

When replacing bearing hub assemblies fitted into aluminum control arms, try heating the control arm with an electric paint removal gun.

In most cases, the aluminum will expand enough to expedite removal of the hub assembly.

Expedite installation by thoroughly cleaning and lubricating the hub’s mounting surfaces.

Replace all retaining bolts as required, apply lubricant or threadlocking compound as directed and torque each to the manufacturer’s specification.

Question: How do you check wheel bearing play?

Answer: Raise the vehicle so the wheel is off the ground, then grab tire at the 12 and 6 o’clock positions and rock the tire back and forth. As a rule, you should not feel any play or looseness if the vehicle has sealed wheel bearing cartridges or hubs with sealed wheel bearing assemblies. On older vehicles with serviceable wheel bearings, a little play is normal but a lot of play is not. Refer to the vehicle’s service specifications for the maximum amount of acceptable play.

Wheel bearing play can be measured with a dial indicator by placing the dial indicator against the hub and rocking the wheel in and out by hand.

As a rule, you should see no more than .005 inches of play in the bearings if the bearings are good.

You can also rotate the tire by hand while measuring play, but be careful not to confuse rim or hub runout

42 August 2014 | TomorrowsTechnician.com

Photo 4: Since this wheel bearing had plenty of lubricant, it’s safe to assume that the failure was caused by a metallurgical problem.

Photo 5: Worn wheel bearings can cause clearance problems at the ABS sensor and store ABS trouble codes. with looseness in the bearings. As a rule, hub runout should be .0015 inches or less, and no more than .002 to .003 inches of runout at the lip of the rim. If runout exceeds this amount, try reindexing the wheel on the hub, or remove the wheel and measure runout on the rotor or hub itself.

If there is still too much runout, cutting the rotor with an on-car lathe can eliminate or reduce runout at the rotor.

The Rotor Report: Drilled or Slotted?

Y

Cashing in on Slots

ou’ve seen them on the race track. You’ve seen them on the street.

You’ve seen them in speed shops, in magazine ads, online and probably on eBay, too. The product we’re talking about is slotted and/or crossdrilled high performance brake rotors. They look great, no doubt about it.

It could be a “bling” thing with many buyers, but it can also be a worthwhile performance upgrade.

It all depends on the application, how the vehicle is driven and whether the customer wants a set of performance rotors for show or for go.

Some serious racers today have gotten away from cross-drilled rotors and now run slotted rotors or ones that use both slots and holes. Slotted rotors typically have four to eight evenly spaced shallow grooves milled into both surfaces of the rotor. The slots provide the same pad venting benefits as holes, but with less risk of cracking because the slots usually don’t extend all the way through the rotor (though some do). The slots are usually angled and curved so they sweep under the entire surface of the pads.

This provides much better venting than a series of holes.

Size Matters

Drilling to Win

One way to increase the cooling capacity of the brakes is to install larger rotors. The bigger the rotors, the more heat they can handle.

Unfortunately, it isn’t easy to change the size of the rotors on many vehicles. Bigger rotors mean repositioning the calipers and/or going with large calipers, too. There are aftermarket conversion kits for some vehicles, but not for all.

Years ago, racers started crossdrilling rotors with small holes to increase cooling. Drilling 30 to 40 evenly spaced holes through the rotors increased airflow and cooling for faster heat dissipation.

The phenolic resins that are used as binders to hold brake pads together give off vapors when they get extremely hot. The gas can form a boundary layer between the pads and rotor that

reduces friction. The effect is similar to that of a plastic puck on an air hockey table.

If the rotor is cross-drilled or slotted, the holes or slots break up the boundary layer and provide a path for the gas to escape. Now the pads can make full contact with the rotors for maximum braking effectiveness even when they are sizzling hot.

Cracking Up Cross-drilling rotors may seem like a great idea, but if done improperly, it can have serious consequences.

Drilling a hole through the surface of a rotor creates a stress point in the metal. If the edges of the hole are not radius chamfered to dissipate the stresses, the hole may concentrate stress to the point where cracks start to form and propagate outward from the hole.

Cracks are something you don’t want in a brake rotor because cracks can lead to catastrophic rotor failure! â–

Under the Hood

KEEPING YOUR COOL Adapted from Scott Gonzo Weaver’s article in

WHEN DIAGNOSING A/C SYSTEMS

L

eave it to the manufacturers to take a simple thing like heat and air conditioning and turn it into an electronic jungle of wiring, sensors and computer components. HVAC units have come a long way from when I started in the business.

Not that I want to dwell on the past, but it might be a good idea to make sure we understand the basics before diving into the problem of today’s systems. I always feel that if I understand a

system fully before doing any repair work, I’m more likely to get it right the first time.

Diagnostic procedures vary from car to car and from year to year. I’m finding more and more these days it’s a lot easier to diagnose the HVAC system with a scanner rather than with a print-out and test light.

With the advent of the electronic door motors and the crazy locations on some of these components, I would definitely try to use a scanner

‘Overcharging’ A/C Service In the world of public opinion, if you heard that technicians were ‘overcharging their customers,’ you might interpret that as an issue pertaining to the customer’s repair bill.

However, in the world of mobile air conditioning service, we’re referring to the problem of some vehicle A/C systems being (unknowingly) charged with too much refrigerant.

A/C performance problems due to too much refrigerant in the system have become an issue in recent years, as vehicle manufacturers have made the move to smaller A/C compressors in order to reduce weight and put less loads on today’s smaller engines.

When we look at the refrigerant demands on older R-12 vehicles that operated under the hoods with V8 and 6-cylinder engines, A/C systems operated on as much as 55 to 60 ounces! Today’s R134-a systems have 12 to 16 ounces of refrigerant to deal with.

That’s not a lot of wiggle room when recharging a system.

What the industry is finding these days is that if you

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service and A/C system, but don’t fully recover all of the refrigerant prior to the work, and then add a full charge to the system, you may run the risk of overcharging. And, an additional 4 to 6 ounces of refrigerant in today’s smaller compressors will cause the A/C system to not operate efficiently, and lead the vehicle owner to return to your shop complaining their “A/C system isn’t blowing cold air.”

So pay extra attention when operating that A/C refrigerant recovery equipment!

when possible. An interesting fact, some aftermarket scanners provide a wealth of information on HVAC systems.

Before purchasing a -scanner, I would ask whether or not it covers HVAC units and which years, which models and how thorough it is.

The more information you have before you get your hands dirty, the better.

One of the more common repairs I’ve seen on both domestics and imports is connections. The manufacturers (in my opinion) have gone to the point of making these connections just barely survivable, but

not for the length of time that consumers are stretching their vehicles’ useable years on the road.

The other item of concern is the control sensors, i.e., high pressure sensor, low pressure sensor, sun load, etc., for the most part, I wouldn’t drag out that test light and start stabbing the wires. They may look like a sensor, they may have wires like sensors, but there’s a good possibility that it’s not a positive or negative signal at the sensor.

In some cases, the sensor maybe reading a digital-type signal (waveform voltage) that would be easier

TomorrowsTechnician.com 47

to read on a scanner screen instead of that 12V test light.

These values are then sent to the PCM to be interpreted and used to determine the actual A/C clutch engagement or door positions.

Here again, a scanner is the proper tool of choice, not the test light.

Assuming we don’t have a component failure and that the entire problem is a connection somewhere, let’s say at the blower switch, which

in some cases is also the “On” switch for the entire system.

If the plastic housing has been melted and the physical “metal” connector is skewed out of place, chances are that no matter how much manipulating you do to “refit” the metal tab back into place, it’s still going to end up back where it started and your customer will be back at your door with the same problem. I would locate a replacement connector either from the dealer or the local parts store.

(I’ve had next to no luck getting a

connector from the salvage yards.

Most of the connectors that came from the salvage yard are just as bad as the one I already have in the car. But, you might get lucky…)

The advantage of using a scanner to see certain sensor values and door positions also has one extra quality to the diagnostic process: Codes. Codes for the HVAC system are valuable information for you as the tech. However, a code is not the answer, a code is a starting point or a direction for repair. So many times I see vehicles come in with new parts bolted in because the last shop that had it read a code and assumed that meant to replace the part.

Beetle-Juice A perfect example of this was a 2002 VW Beetle that came in with a brand-new compressor and fan

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48 August 2014 | TomorrowsTechnician.com

Photo Courtesy: German Audio Tech

controller on it. There was a code stored for poor compressor performance at idle, which was exactly what it was doing.

If the car was at idle and the A/C was off, rev the engine just slightly and the compressor would turn on and work perfectly. Bring it back to an idle and the compressor would shut back off.

Checking into it a little further, I found the real culprit to be the charging system. At an idle, the alternator couldn’t develop enough output to maintain all the systems in the car.

Since the computer wasn’t getting enough ‘juice,’ the PCM would shut down the A/C while trying to maintain a voltage level that was acceptable.

But this level never got to the point of causing the charge indicator to come on during this whole process. (Cars are getting too smart these days.)

The best thing I can tell you about diagnosing HVAC systems is to consider the year and make of the car, find out whether or not a scanner can code, read values and/or give you some information on the condition of the components before you start changing things. If there isn’t access by way of a scanner, then I would suggest a wiring diagram and a description page that will inform you of how each component works in that given system.

If you keep your cool, I’m sure you can get it diagnosed and repaired before your customer gets too hot. ■

TomorrowsTechnician.com 49

Tech Tips

FIRING ON ALL CYLINDERS? Running Compression Test is a Great Tool for Diagnosing Density Misfires

A

running compression test or dynamic compression test is an important, but littleused and often overlooked engine diagnostic tool. Why is this test so significant? It can be used to pinpoint the cause of a misfire when all the usual tests return normal results. It’s also used by performance tuners to verify that each cylinder is contributing equally to the engine’s overall power output.

When you perform a static compression or cylinder leak-down test, you’re checking the sealing capability of each cylinder. A vacuum test is a great way to determine an engine’s overall breathing capabilities, but does not provide results for individual cylinders. The advantage of a running

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August 2014 | TomorrowsTechnician.com

compression test is that it gives you an idea of the volumetric efficiency of each cylinder. In other words, how efficiently each cylinder is pulling air in, retaining it for the correct amount of time, then releasing it into the exhaust. If a cylinder cannot perform these functions properly, the result can be a loss of volumetric efficiency or a density misfire.

How to Perform the Test 1. Create a chart similar to this example to record your test readings.

2. Begin with a normal ("static") compression test on a warm engine to eliminate obvious problems such as badly worn rings, burnt or bent valves or holes in pistons. If you have a diagnostic trouble code, you may know which cylinder is misfiring, but it’s a good idea to test the compression of all the cylinders in that bank to get a good comparison. Record your static compression readings.

3. Install all of the spark plugs except the one for the suspected cylinder.

that is much lower than the other cylinders. If a snap reading is low (much less than 80% cranking compression), look for air intake problems such as severe carbon deposits on intake valves, worn cam lobe, worn valve guides and springs, rocker or push rod problems, or "shutter valve" miss-positioned in the runners of a variable runner intake system.

WARNING: GROUND THAT PLUG WIRE TO PREVENT MODULE DAMAGE, OR WHEN EQUIPPED WITH A COIL-ON-PLUG IGNITION, SIMPLY DISCONNECT THE COIL HARNESS PLUG.

4. Disconnect the injector for that cylinder on a port fuel injection system.

5. Install your compression tester in the suspected cylinder. The test can be done with the Schrader valve removed, but most techs recommend leaving the valve in the gauge and "burping" the gauge every 5-6 "puffs."

6. Start the engine and take an “Idle” reading. Be sure the idle speed is a consistent 1,200 rpm. Record the results.

7. Now, from 1,200 rpm, snap the throttle to 2,500 rpm and release quickly. Reading should rise. Record the results.

NOTE: Don't use the gas pedal for this snap acceleration. The idea is to manually open then close throttle as fast as possible, forcing the engine to take a "gulp" of air.

In Example 2, cylinder #4 has a higher than normal snap test reading. If a Snap measurement is significantly higher (over 80% of cranking compression), it means the air is not leaving the cylinder efficiently.

Look for problems on the exhaust side of that cylinder such as worn cam lobe, bent push rod or collapsed lifter. If the snap readings are all high, look for exhaust restrictions such as a clogged catalytic converter or muffler.

Sample Test Readings Comparing measurements between cylinders is important. Running compression at idle should be 5075 PSI (about half cranking compression). Snap throttle compression should be about 80% of cranking compression. Let’s analyze the results from the following sample test readings.

In Example 3, cylinder #2 has a low Idle and snap test reading. These types of numbers indicate that the cylinder is not holding compression efficiently. Look for issues such as slightly bent or burned valves, excessive carbon build-up on valves or seats, worn valve guides and springs, scored cylinder wall, or a leaking head gasket.

As you can see, information gathered from a running compression test can be very helpful when diagnosing misfires and tuning for total engine performance. It’s a great test to add to your diagnostic arsenal.

In Example 1, cylinder #1 has a snap test reading

Source: ALLDATA Community Diagnostic Team ■ TomorrowsTechnician.com 51

CrossWord PuZZle

ACROSS

Tomorrow’s Technician August Crossword

1. Cylinder sliders 5. Components returned for remanufacture 8. Unexpected engine stoppage 9. Combustion ____, explosive area 10. Inertia ____ seat belt 11. Mirror image (4,4) 13. Franchised vehicle vendor 15. Two-prong fastener, ____ pin 18. Ruined-fastener description 19. CV-joint cover 22. Engine-hood support (4,3) 23. Cylinder-repair sleeve 24. Showroom transactions 25. Increases cylinder's diameter

DOWN

Solution at www.tomorrowstechnician.com Continued from page 14 Cruiser are fabricated from light-gauge steel, sealed with a silicon sealer, and then painted for protection from corrosion. An adapter plate was fabricated to mate with the transmission bell housing, hold the electric motor, and to maintain the alignment and spacing between the two components (see Figure 6). Depending on the torque rating of the motor, special motor mounts or straps might be needed. Initially, the project was designed with the original motor mounts, but a high-performance solid rubber mount later replaced this design.

Since this project was designed to utilize the originally equipped clutch system, a special coupler was designed to connect the pressure plate and electric motor together.

There are ways to have a clutchless system by fabricating a coupler to connect the electric motor output to the transmission input shaft. However, regardless of whether the vehicle will utilize a clutched or clutchless system, a dampening component must be used to suppress the shock of the motor.

If all the parts are properly fabricated, assembly should be simple. The next step would be to route and connect the motor, controller, batteries and charger. To prolong the lifespan of the batteries, it is important to maintain the batteries while they are not in use. Allowing lithium-based batteries to fully discharge will ruin the cells.

Testing The last phase entails testing the powertrain, charging and

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August 2014 | TomorrowsTechnician.com

1. Valve-train part, perhaps 2. Cooling-system deposits 3. Engine lubricants 4. Six- or twelve-point tool 5. Online discussion venue (4,4) 6. Replacement-part description, perhaps 7. Tapered fastener 12. Carmaker-recommended replacements (1,1,1,5) 14. Race-car downforce device 16. Adjusts ignition timing, in a way 17. Power-boosting exhaust manifold 18. Tire-tread slits 20. Pink-slip name 21. Collector-car collectors' collective

brake system. Testing the powertrain starts by lifting the vehicle off the ground to verify that the motor can rotate the wheels. At this point, it’s important to keep an eye on the amount of current the motor is drawing. The controller will dictate the amount of current in the system. Due to counterelectromotive force, it’s normal for the motor to draw higher current when accelerating from a stop and decrease as the motor’s rotational speed increases. Diagnosis of the controller and motor must be performed if the motor exceeds the rated current draw.

It’s also important to keep an eye on the amount of current the system is drawing when testing the charging system.

Absorbed glass mat (AGM) and lithium-based batteries require a specific type of charger that monitors charging current. The system should taper charging current as it reaches max capacity and each cell should fully charge at the same rate. Unfortunately, overtime each cell will deteriorate at different rates. The result is that each cell will fully discharge and recharge at different rates. This imbalance within the battery pack can decrease total capacity.

Furthermore, the imbalance will cause the charging system to either over- or undercharge some cells in comparison to the other cells and cause the battery pack to fail. There are services specifically targeted for the hybrid market to recondition battery packs by balancing all of the cells. Current is drawn from each cell, pulling the voltage of each cell down to the same level, and charging each cell to max capacity based on each specific cell status. This reconditions any deficient cells to be on par with the rest of the battery pack. ■

DIRECT CLASSIFIEDS

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August 2014 | TomorrowsTechnician.com

Report Card

According to its designers, the Jeep Cherokee Dakar is the most extreme Cherokee ever.

The vehicle made its debut on the trails and rugged terrain at the Easter Jeep Safari in Moab, Utah in April.

Now in its 48th year, the Easter Jeep Safari is attended by thousands of die-hard off-road enthusiasts looking to enjoy a week of serious off-roading on some of the country’s most renowned trails.

There, they got to witness the Dakar concept’s silver steel satin gloss exterior skin, strikingly set off with flame red graphics that encircle the window and wrap around the black hood graphic.

The Trailhawk 17-inch polished satin clear coat wheels feature two large flame red pockets, along with the with the Cherokee nameplate.

Front-end features are enhanced by

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By Ed Sunkin, Editor

two prototype inserts on the traditional Jeep seven-slot grille, as well as through a prototype lower fascia trim.

Cherokee Dakar is fortified for offroad action, equipped with Jeep Performance Parts rock rails, an oil pan skid plate, front suspension skid plate, two-piece fuel tank and underbody skid plates.

Cherokee Dakar’s wheel openings have been modified in order to accommodate larger 33-inch BFGoodrich Mud Terrain tires. The rough-and-ready look rises with a prototype Jeep Performance Parts lift kit, and additional suspension

August 2014 | TomorrowsTechnician.com

modifications help make it the most extreme Cherokee yet.

And the prototype wider fender flares with riveted bolts give a tougher appearance and also accommodate the wider track and larger tires.

Cherokee Dakar’s crawl ratio is 48:1, and estimated approach and departure angles are 32 and 39 degrees, respectively.

Inside, Katzkin leather black seats with “Machined Gunmetal” inserts are heightened with Header Red stitching, which is also found on the steering wheel, armrest and shift boot.

“This year, we’re showcasing a combination of Mopar and Jeep Performance Parts on our vehicles for off-road enthusiasts to see a variety of customization and personalization options,” said Pietro Gorlier, president and CEO — Mopar, Chrysler Group LLC’s service, parts and customer-care brand. “Since 2002, Jeep and Mopar have teamed to create more than 40 unique concept vehicles for enthusiasts who attend the popular Easter Jeep Safari.”

Although the concept vehicle was powered with the 3.2L V6 stock motor, the Jeep/Mopar crew did tweak to the exhaust to make the Dakar purr like a mountain lion when the gas was applied. Which was fitting, given the location of the annual event. ■