Just as the heat of summer brings us unique service opportunities, so does the approach of Old Man Winter – especially if you live in the Snow Belt! Even if you live in a part of the country where the difference between summer and winter is hardly noticeable, you can still use this time of year to market important maintenance services to your customer. And while I think that these system inspections are something we should all be doing year-round, they tend to lend themselves to special attention in the minds of our customers when the mercury in the thermometer begins to dip.
Cooling system check – Belts and hoses
The cooling system is one that seems to be more on the mind of consumers in the winter than the summer. Easy to understand why – the first time the cabin won’t warm up is almost as bad as the first time it won’t cool down when it’s hot outside! Interesting how our customers are so keen on cabin comfort, even when we recommend much needed work on their vehicle’s safety systems, isn’t it?
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| The “PK” number (circled) is a standard metric designation for belts that can help you select the correct replacement when you’re stuck. The first number (6) is the number of ribs, “PK” means metric, and the last number (1256) is the “effective” length (not the actual outside circumference). |
Begin by performing an overall inspection of the cooling system components. Inspect the level of coolant in the recovery bottle and note its condition. If the level is low, inspect for signs of leakage. Even small leaks can lead to air in the system and that can lead to premature depletion of the coolant’s additives and system component damage. Keep in mind, too, that the leak may be internal so no signs on the outside doesn’t mean a leak doesn’t exist!
Let’s inspect the accessory drive belt next, since in many cases it drives the all-important water pump. Since nearly every belt today is made with EPDM and can be worn out well before you see any visual indications, you’ll need a belt wear gauge to perform this check.
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The tools vary depending on who makes them, but the objective is the same. As an EPDM belt wears, the ribs become narrower and the grooves wider. This wear pattern allows the belt to fit more closely to the pulley and that’s not a good thing. As the belt moves in, the gap between the belt and the pulley that allows a path for water to escape decreases to the point that the belt can actually hydroplane when operated in wet weather. Additionally, the wider spacing in the grooves reduces the interference friction that keeps the belt from slipping. A slipping belt may not make noise but will operate hotter than normal. This extra heat is passed on to the components that the belt drives, leading to accelerated wear and premature failure in their own pulley bearings.
If you don’t already have one of these wear gauges in your toolbox, check with your parts suppliers and if that fails you can always reach out directly to any of the major belt manufacturers for one. For more tips on checking and servicing belt issues, check out our Trainer video on the subject at https://youtu.be/71toy_rpUbA.
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| To accurately measure the mixture ratio of the coolant, use a refractometer. Test strips are also available to help you gauge the coolant ratio. |
On to the hoses. The biggest cause of cooling system hose wear is electrochemical degradation, or ECG, and it’s not easy to detect. ECD attacks the rubber from within and is caused by the acids developed in coolant over time. Check the hoses by squeezing them between your thumb and forefinger. The hoses should feel soft and pliable. If they feel tight or crunchy, they may require replacement. Take a close look at the hose connections, looking for signs of softness, bulging (especially when the system is under pressure), or cracks that could be signs of damage caused by ECD or age.
Even if the hose appears to be ok, a good rule of thumb is to recommend hose replacement when a hose is over five years old.
Cooling system check – coolant
Coolant can last a long time if maintained. Look at our HD cousins as an example. Class 8 trucks routinely go 400,000 miles or more on a single coolant service. The difference? The health of the additives included in the coolant is checked and maintained regularly!
These additives play important roles. Some work hard to delay the degradation of the coolant, preventing acidic decomposition by-products from entering the system. Others provide lubrication for cooling system components and seals, while others protect against corrosion. In the automotive sector, we don’t test for these additives specifically but we can perform a few simple tests that will allow us to gauge the condition of the coolant overall so that it can be replaced if these additives are depleted prematurely.
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| Use a test strip to measure the pH and reserve alkalinity of the coolant. If reserve alkalinity is low, but pH is correct, advise your customer that the coolant will be needing service in the near future. |
And that happens more than you may think. A small leak that slowly depletes the coolant recovery tank may be refilled with tap water, diluting the mix and introducing contaminants in the system. A cylinder head gasket leak, even though it isn’t causing a drivability issue, may be present and allowing exhaust gasses into the system and that will lead to acidic build up leading to ECD. A bad electrical ground can cause underhood circuits to seek a path back to the battery via the coolant, also leading to ECD. So even if you personally serviced the cooling system last season, inspect it again just in case!
Start with inspecting the mixture ratio of the coolant. Take your sample from the radiator rather than the recovery tank in case someone has added straight water or coolant to the system. That will throw of your test results. I prefer to use a refractometer myself but there are test strips that you can use for this purpose. Don’t use the old hydrometer your dad used back in the ‘70s!
The mixture should be between 40 percent and 60 percent. Too much water will lead to corrosion problems and too little will interfere with heat transfer. If the next test passes, you can adjust the mixture by adding water or the proper coolant as needed.
The second test is to measure the pH of the coolant. This is a great indication of the coolant’s condition and typically will become more acidic as the additives are depleted and the coolant degrades. This is the root cause of ECD. As the coolant becomes acidic, the cooling system component metals start reacting, turning the system into a battery cell that you can actually measure the voltage in! In fact, I’m betting many of you were taught this as a method for inspecting coolant condition. There’s a little more to it than that but I don’t have the space to dive into that topic today!
If the coolant pH is out of range, you’ll need to do two things. First, you’ll need to service the cooling system and replace the degraded coolant. Second, you’ll need to be sure you’ve identified why the coolant degraded especially if the coolant has failed well before its normal service life. For more info on testing coolant, check out this Trainer at https://youtu.be/zY4YDncoYoI.
Don’t forget the battery!
The battery’s state of health is increasingly important with the growth of electronics used on the vehicle. And we all know that a dip in temperature can quickly point out the weaknesses in a battery that tested fine the day before.
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| It takes only a few minutes to test a battery and the charging system using a scope and the resulting capture can provide so much more information that conventional testing methods. |
My personal preference for battery testing is the scope method. I’ve found weak batteries that tested fine otherwise with this method and it’s a great excuse to set up your scope as part of your regular morning routine. Because the scope captures data so much faster than conventional testing equipment, expect to see some strange things the first time you try this!
For example, we all know that normal starter draw is somewhere around 150 amps, depending on the size of the engine and its compression. But that’s after the starter has the engine turning. In the few microseconds before that, the amount of current needed to get that mass moving is significantly higher – and you’ll see that on the scope. Over 500 amps is not unusual and is referred to as “in rush” current.
Along with high current for a few microseconds, you’ll notice a larger battery voltage drop occurring at the same time. We’ve been taught to look for loaded voltage levels no lower than 9.5 volts when testing conventionally, but that “norm” drops to 8.5 volts when using a scope.
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| Using your Min/Max function, you can perform a quick “down and dirty” battery test that will give you Open Circuit Voltage (OCV), loaded voltage and charging system voltage in about three minutes. |
In addition to the battery performance, you can visually see current passing through the starter solenoid contacts, failed diodes in the alternator (both in the voltage and current patterns) and other system problems. You also have a “picture” you can share with your customer when recommending any needed repairs. Add an ignition reference, and you can also do a quick check of the engine’s timing and mechanical health using the relative compression test. The scope connections are the same.
And yes, we have a video you can watch on how to perform this test! https://youtu.be/dZSyshg0GfE
Certainly, the fall provides additional opportunities to check the overall condition of your customers’ cars with a focus on these traditional areas. But helping your customer maintain their vehicles in peak condition is not a seasonal thing – it’s a year-round thing!