CCJ

July 2018

Fleet Management News & Business Info | Commercial Carrier Journal

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32 commercial carrier journal | july 2018 Know when and how to change coolant correctly BY JASON CANNON T he protective additives in engine coolant can become depleted over time, resulting in a loss of corro- sion-fighting properties. If undiluted coolant and coolants of different types are continuously topped off with water, it can lead to further degradation of the fluid's freeze and boil protection. "Contaminants like exhaust gas, oil, manufacturing residues, methane and sulfate can enter the cooling system and increase corrosivity," said Dr. David Turcotte, director of technology and product development for Valvoline. Colin Dilley, vice president of technology for Prestone, said coolant degrades because of three main reasons: In- hibitors are used up and unable to prevent corrosion from occurring; chemical incompatibility with certain cooling system parts; and the breakdown of the ethylene glycol that provides freeze and boil protection. Changing intervals Years ago, coolants lasted up to 36,000 miles, but because of the integration of more durable organic inhibitors, today's heavy-duty coolants can reach 600,000 miles, with many warranted to 1 million miles. Turcotte said that while it's always best to follow the man- ufacturer's guidelines for fluid choice and change intervals, there are multiple ways to approach coolant maintenance and cooling system service. "e more severe the duty, the tougher it is on the cool- ant," said Stephannie Crane, division brand manager for Peak Commercial & Industrial. "Everything is affected by how challenging the duty cycle is." Dilley said the engine's age will dictate significant differ- ences in cooling system maintenance. "Older systems used to leak, which would create a natural replenishment as users topped them off to keep the system full," he said. "However, new cooling systems don't leak like they used to, so now the fluid may only last 20,000 miles before damage starts to occur." Out with the old Once the coolant has lost its ability to protect against freeze and boil-over, it needs to be replaced. Aer a traditional drain, a minor amount of the older coolant remains in the system, which means the new coolant is starting out with some degree of depletion. "It would be better to flush out the old coolant with water to replenish the whole system," Crane said. "You have to have the proper mix of coolant and water in the system when you are done." Dilley said flushing also cleans out any corrosive by- products that may be present and also helps prevent future blockages from occurring. Turcotte said gravity usually will drain the majority of old coolant from most heavy-duty vehicles, but machines that evacuate and replenish the cooling system provide a better way to replace all the fluid and control any waste for proper disposal. "It's important to remove all the old fluid and refill com- pletely with the new fluid," he said. "Always top off with the same coolant, properly diluted, during service." The right water Prediluted coolants are mixed with deionized water, but most concentrated coolants are designed so they can be diluted with water of any reasonable quality. Turcotte said water should be demineralized, which helps prevent hard water scale and deposits in the system. "How- ever, water of drinking quality is the minimum acceptable choice for dilution," he said. Water that is full of salts, chloride or hard water will cause deposits and eventually block the radiator, Dilley said. "Chloride in the water, which is common in wells aer a win- ter of salting the roads, will accelerate the corrosion of all metals, lower the engine life and reduce performance," he said. "Why go through all the work to properly flush and fill a system and buy a high-quality coolant, but then cause potential damage with the least costly material around?" in focus: COOLANT SYSTEMS Prediluted coolants are mixed with deionized water, but most concentrated coolants are designed so they can be diluted with water of any reasonable quality.

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