NARSA/IDEA’S NEWS


Most Common Mistakes Involving Engine Coolant


OVER 40% OF HEAVY-DUTY engine downtime is coolant related! The number one reason noted by ASTM and The Technology and Maintenance Council for diesel engine repair is caused by failures in the engine cooling system. So, what are the most common mistakes involving coolant, and how can we stop this trend? Let’s first look at a few statements from technicians in the field related to this problem.


“The only difference in coolant is the color.” “They are all the same.”


I have often heard these statements during my trainings from technicians in the field. That is clearly not the case. When I ask a technician, “What test procedures do you use in your shop for coolant?” The answers I receive are either, “We keep the surge tank full” or “Oh, we use Extended Life Coolant. You don’t need to test that coolant.” Tell that to my buddy Patty in Westchester County, New York, who operated ten vocational refuse vehicles and needed to rebuild six engines due to liner pitting.


The buyer for the County Transit System stated, “We put our coolant out to bid and buy our coolant based on the lowest price.” Well, the bid winner was a poor recycler around the transit system. The county needed to repair the head gaskets in 100% of their fleet powered by diesel and CNG/ LNG engines. There are so many more misconceptions on engine coolants. Let’s provide you with some guidelines to follow and make sure you make the right decisions whether you are maintaining your fleet or if you are an owner operator trying to keep your pride on the road.


The first thing to remember when choosing a coolant is “Let The Buyer Beware.” If a coolant is way underpriced, you are going to get what you pay for in hefty repairs down the road. Buy your coolant from a reputable blender selling a known brand name and that meets the specifications of ASTM D-6210, TMC RP-329, or of the engine manufacturer. Next, we recommend your fleet buy one coolant that meets the specification of your fleet. Do not buy multiple brands of coolants. Once you have made the decision on which technology works for your fleet, implement a simple maintenance program for coolant.


Keep this simple for your technicians. Test the coolant for color, clarity, pH, freeze point and chemistry.


Follow these basic rules:


1. If you are using RED colored coolant, and the sample is not red, then someone may have added another technology to the system.


2. Check the sample for clarity. We do not want to see debris, cloudiness, oil, or carbon. The sample should be clear as new. If a pH test meter or test strip is available, be sure the reading is between 7.0 to 11.0. If neither is available in your shop, simply smell around the system. If an odor of ammonia is present, there is an issue. If you must drain, clean, flush and refill the system if there is a failure in odor, the reading is outside the pH range, or if the color is black or brown.


3. Check the freeze point. The most accurate tool in the shop is a refractometer. Do NOT use test strips


By: Joe Long, Old World Industries Senior Field Technical Trainer, jlong@ owi.com


to test the glycol content. They are not accurate and may be off by as much as 50 degrees F. The acceptable range for freeze point for all heavy-duty OE’s is a minus 12 to a minus 65 degrees F (40 – 60% glycol / water mixture).


4. Use a chemical test strip to see if the coolant in your system has enough inhibitors to continue protecting your engine cooling system. Check with your supplier to be sure you are using the correct chemical test strip. If a coolant has Nitrite in the inhibitor package, you should use a test strip to test for Nitrite levels. If your vehicle is using a Nitrite Free coolant, it is logical that you should not use a Nitrite test strip, but rather a test strip that tests the Organic Acid level.


Look for more tips on tap water, glycol concentrations, SCA additives, and Nitrites in upcoming issues of The Cooling Journal.


September/October 2021 | THE COOLING JOURNAL | 17


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