Cooling system basics

Next Article

Technical

BASICS

of squeezes and notice if the hose seems very soft or squishy to the feel. It’s possible the barrier wall inside the hose has deteriorated due to an unknown substance like oil or another chemical that has broken down the barrier. That could be a rupture waiting to happen, especially under a high pressure high heat condition.

Other external leak points can be at the water pump weep hole, heater core inlet and outlet hoses as well as the core itself. Other potential leak areas include intake manifold gaskets, cylinder head gaskets, thermostat gaskets and cylinder head or block freeze plug areas. The radiator can develop leaks at the core and especially at the seams of the tank.

Newer vehicles, as you know, have plastic tanks that are attached to an aluminum core. That particular area is prone to start leaking.

COURTSEY OF SOUTHEAST MOBILE TECH

The methods you use to check for leaks are the same today as you performed in the past. Systems under pressure always tend to show a leak a lot faster than one that’s not under pressure. That’s not to say a system can leak without pressure as in some conditions a leak will show up under an ambient temperature state.

Belts and pulleys So what makes a coolant system operate besides having the correct coolant and the right amount of it? It’s the mechanical moving parts that place the system in motion. Those parts consist of a water pump, serpentine belt tensioner, an idler pulley or two, a power steering pump, an air conditioning compressor, and the alternator (see Figure 3 on the next page).

All of those things are tied together with a serpentine belt or a combination of serpentine and/or V belts. When checking the mechanical aspect of the cooling system, every component has to be operating correctly. The part that is the most crucial is the belt.

Depending on the vehicle, a combination of multiple belts could be used. If they break then everything stops. The belt is also the component that is the weakest. If a component starts to fail, the belt will tend to slip on the pulley thus creating an excessive amount of heat.

Over time the belt will become worn or glazed and it will stop gripping the pulley. You can tell that a belt is glazed by not only looking at the belt for a shiny appearance, but it feels a little more brittle and not quite as flexible as it should be.

Look for any cracks that tend to develop on the wearable part of the belt as those could be potential failure points. Belts also tend to fail due to different chemicals like oil and coolant leaking on them as well as a sharp object rubbing on them.

Figure 3: This shows the belt drive system of a 5.9L Cummins engine.

Make sure that there are no external leaks found before a new belt is installed. If you don’t, the new belt life span will be decreased signifi cantly.

Belts should have the proper alignment checked before installing a new one. Using a belt alignment tool can aid in proper alignment (see Figure 4). The alignment can be off due to a few factors such as an accessory not properly installed or an incorrect pulley being used on that accessory along with a pulley spacer being used or not being used.

Remember to visually look at the new component that you are replacing and make sure it’s exactly like the one you removed.

Have you ever heard a chirping or squeaking noise while the engine is running? Chances are that noise is coming from the belt gliding over the pulleys. Some of the pulleys on the vehicle may feature a series of grooves. What could be happening is there is a buildup of dirt or debris getting inside those grooves and when the belt is turning, the ridges from the belt aligning in those grooves will create a noise that can be annoying to the customer.

When you are replacing a belt, before you install the new belt, look over all the pulleys and remove any debris you see in the grooves of the pulley. This goes for smooth pulleys as well.

Use a small wire brush and spin the pulley while cleaning the area of the pulley. While 26

wearing safety glasses, use a small amount of compressed air to blow away excessive debris from the pulley. We know that the pulleys need to be clean and in good shape so our belt will grip them correctly, but what about pulley condition? Pulleys need to be free from damage both visually and mechanically. When performing a check on a pulley, make sure that there aren’t any extra grooves worn into the pulley, nicks or burrs that have developed on the pulley, especially when dealing with plastic pulleys.

Check that the pulley isn’t excessively worn, as the belt will wear a pulley down over time even though there isn’t any damage to the belt system. The pulley must feature the correct diameter for the application. If any of these inspections reveal an issue, replace the pulley.

Also check the pulley for excessive sideto-side play. The pulley rides on a bearing or features an integrated bearing. Spin the pulley with the belt removed and listen for noise that may indicate wear or grit. When you spin the pulley you will also be able to feel the drag of the bearing it rides on. Excessive drag, noise, along with too much play is cause for a pulley replacement.

Pulleys that fail can damage the component they ride on along with the belt. Sometimes a nearby component can be damaged. For example, if a broken pulley or belt gets ejected into

COURTESY OF SOUTHEAST MOBILE TECH

Figure 4: Belt alignment tool.

the radiator and punctures the core. You just went from a $50 pulley repair to a $200-plus radiator repair.

These pulley checks should be performed on every component that the belt rides on. Make sure that all accessories are operated for normal belt operation. Air compressors need to be turned on, power steering pumps should be operated from steering stop to steering stop and alternator efficiency can be checked by loading the electrical system and making the alternator work.

Water pump Another component that needs to be checked closely is the water pump. The water pump’s job is to circulate coolant in and around the engine. Obviously a malfunctioning water pump can create a lot of havoc. Water pump designs can vary among today’s vehicles. There are pumps that are belt driven and some are electrically driven. Some belts are driven by the engine’s timing belt.

When you are performing a cooling system check you typically don’t check a timing beltdriven water pump due to its difficult access. But if you are doing a timing belt service, a water pump replacement in my opinion is a necessary step and part of the job. I don’t have to tell you what can happen to a timing belt if a water pump fails that’s being driven by a timing belt.

As with a conventional cooling system check, you check the timing belt components just like you would any other belt driven component. When checking an engine’s water pump that’s belt driven, look for the water pump’s weep hole for signs of excessive leaking (see Figure 5).

Check the mounting of the water pump for leaking gaskets, missing mounting bolts and or loose bolts. Inspect the pulley like you did with 28

Figure 5: Water pump weep hole leaking.

the previous pulley inspection.

If the customer is stating that the engine is running hot, then check the water pump flow at the radiator fill neck or tap into a coolant hose and check for proper flow. A water pump impeller could be broken off completely inside the pump or the impeller could be missing pieces (see Figure 6).

If flow is suspected of being a problem then removing the water pump from the vehicle for a visual inspection will be needed.

Checking the belts, the different pulley components and the rest of the components that make up the parts of a properly functioning cooling system is essential to keeping the engine running at the proper temperature and efficiency. A cooling system that’s not working properly will also have a profound impact on the air conditioning system.

If the engine isn’t running cool (temperature too high) the air conditioning system will run poorly. If the belt is slipping on the air compressor pulley and not spinning the compressor’s pumping ability fast enough, the A/C system won’t be able to do its job properly. That’s just one reason a careful inspection of the components involved in the cooling system is extremely important.

As I mentioned earlier, modern cooling systems still use a lot of the same components as the older style systems. The difference is that there are more components involved and they are more efficient in keeping the engine run-

COURTESY OF NAPA AUTOTECH

Figure 7: A vehicle in for service, a Ford Focus.

incorporates a shutter vane type system that monitors and controls air flow through the grill. This is just one aspect that may be found in a late model cooling system.

When a vehicle rolls into your service bay, make sure you do your due diligence and give that vehicle a good inspection. Checking and preventing premature failures before they happen will not only keep the engine cool and working properly, but you will keep the customer cool as well.

Preventing the customer from overheating is what makes a repeat customer for life. ■

Figure 8: Here’s a radiator grill shutter.

Edwin Hazzard owns South East Mobile Tech in Charleston, S.C., which is a mobile diagnostic and programming service providing technical service to many automotive and body repair shops. He has 36 years’ experience in the automotive industry. He currently is an automotive trainer, a board member of TST (Technician Service Training), a member of the MDG (Mobile Diagnostic Group), a member of the Professional Tool and Equipment advisory board for Pten magazine, a committee member of Nastaf, and is a beta tester for multiple tool makers.

SUBMIT YOUR TIPS TO ‘TECHS HELPING TECHS’

The December 2019 issue of Auto Service Professional will feature our annual ‘Techs Helping Techs’ secti on, where you have the opportunity to share your technical knowledge with all of our readers.

In the course of your daily work routi ne, you’ve gained real-world insights regarding diagnosing and repairing a variety of vehicle issues. In order to share your wealth of knowledge and experience with your brothers and sisters in shops across the country, we welcome you to submit any ti ps that you feel would benefi t all of our readers.

Subject matt er and length of the tech ti p is wide open. We welcome anything that you feel worthy of sharing. And please share a photograph!

Do you have an ingenious way to fi x a common problem? We want to hear about it!

Make sure you include your name, the name of the shop, the address, and an email address and phone number. The deadline for submissions is Nov. 3, 2019.

Please submit your tech ti ps to mike.mavrigian@bobit.com. Dan Warner, owner of Exoti c Motorwerks in Scott sdale, Ariz.,

Thanks for sharing to im- has gained a far-reaching reputati on as the “go-to guy” for prove the industry as a whole. Porsches and other German marques. Please share your ti ps with your fellow technicians for domesti c and imported vehicles!

GREAT BEAR AUTO

Advocating for women drivers is a priority

AAudra Fordin’s shop was not selected for this reader profile article because she’s a female in a predominantly male occupation. Far from it. Rather, she represents a new breed of repair shop owners and technicians who go out of their way to educate customers, specifically female customers. ALL PHOTOS COURTESY OF ???????????????

Ever since taking control of the shop that her great grandfather started, Fordin has pioneered an effort to educate female vehicle owners in order to increase their comfort level by dealing with a “female friendly” repair shop. Toward this end, she founded the “Women Auto Know” program, conducting free workshops Great Bear Auto owner Audra Fordin. open to female customers to learn more about both As Fordin explained, “What’s so awesome automotive maintenance and safe driving. about my shop is our philosophy, the foundation

“Many females are intimidated when dealing and the purpose for business. We strive to be rewith a repair shop. My goal is to educate them latable to our customers, especially women, so that so that they better understand their vehicles and they feel comfortable when dealing with auto rewhat’s involved in diagnosing and repairing them, pair.” which allows them to better communicate with the technician,” she told us. Does your shop offer general automotive repair

As her program earned increased media atten- or do you tend to specialize in specific makes or tion, Fordin was approached for speaking engage- types of repairs? ments and even a few television appearances. Rev- We provide general repairs for all makes. enues earned for these activities have been donated to a fund to aid in the vehicle repairs for single What is your business philosophy? mothers. We established a “Women Auto Know” four-part

As a by-product of her tireless altruistic efforts, philosophy: the shop’s customer base and profits have soared. 1. Educate not intimidate 2. Show and tell 3. Tell not sell 4. Service not sales

An innovative shop owner, Fordin has committed a substantial amount of time and effort to aid her female customers via her “Women Auto Know” program.

32

“Quite often, when a female driver is told that her vehicle needs certain repairs, they feel uncomfortable or intimidated because they don’t understand the issue or the repairs that may be needed. By educating them, they are in a position to better understand why a repair or type of maintenance is needed. By a ‘show and tell’ approach, we walk them through a hands-on inspection or repair. Seeing a part or repair up-close educates and re-