Over 40% of all diesel engine downtime is coolant-related, says Joe Long, director of sales-Power Fleet Div. at Penray Companies. “Today’s advanced engine technologies can be more susceptible to premature failure and damage from contaminated or substandard coolant. An understanding of the differences in coolants may help reduce cooling system failures that could lead to premature engine wear and failure,” he says.
Modern heavy-duty engines produce extremely high amounts of heat, points out Colin Dilley, PhD, director of technology for Prestone Products, in a company technical report. “Excessively high internal temperatures can . . . cause increased NOx emissions, and possible hot spots that can cause pre-ignition, oil degradation, and thermal distortion,” he says. “All of these conditions can have an adverse effect on engine performance and lead to premature breakdown or failure.
“In order to eliminate these potential problems and deliver optimal performance,” Dilley continues, “modern-day heavy-duty engines need a similarly advanced cooling system and a careful operating balance between the cooling system’s various components and the coolant that is used. In short, cooling systems are best served when they use specially formulated antifreeze/coolants that have been designed to meet the demands of the current generation of heavy-duty engines.”
Most antifreeze is largely comprised of ethylene glycol as the base and a smaller proportion of water and additives, notes Long. A small fraction of the antifreeze market uses propylene glycol as the base, but it’s usually more costly. Generally, a 50/50 mixture of antifreeze and water is installed in the engine’s cooling system. Additives called inhibitors are included to protect metal surfaces. As coolant is used, inhibitors deplete and may need to be replenished with supplemental coolant additives (SCAs), especially when using fully formulated conventional antifreeze.
Conventional antifreeze is known as inorganic acid technology (IAT). To help extend intervals and simplify maintenance, extended life coolants (ELCs) have been developed. ELCs utilize organic acid technology (OAT) as an inhibitor to help protect metal surfaces in the cooling system. ELCs may also contain inhibitors known as nitrited organic acid technology (NOAT). ELCs based on other types of inhibitor technology or using both IAT and OAT chemistry are known as hybrid organic acid technology (HOAT).
Modern-day formulations of heavy-duty antifreeze/coolants have been specially designed to deliver engine protection. The Prestone Command line of antifreeze/coolants includes ELCs, a blend of ethylene glycol and an OAT inhibitor package designed for heavy-duty cooling systems.
KOST USA offers several heavy-duty coolant/antifreeze products, including Heavy Duty Pre-Charged, Global Heavy Duty Extended Life, Heavy Duty Extended Life, and Heavy Duty Nitrite-Free.
Old World Industries makes Final Charge coolant/antifreeze products for heavy-duty cooling systems, and Fleet Charge, a fully formulated supplemental coolant additive precharged coolant/antifreeze.
Penray offers a variety of cooling system products, including Pencool 2000, a liquid formula that reduces scaling and corrosion and acts as a lubricant in the cooling system. Also available is Pencool 3000, a cooling system treatment that helps prevent the formation of gel deposits.
Evans Waterless Heavy-Duty Coolant (HDC) is a proprietary and patented blend of synthetic materials and soluble additives. Evans HDC protects engines, the company says, because it boils at a much higher operating temperature than water used in conventional coolants. Additionally, while traditional coolant contracts and becomes thick at extreme cold temperatures, Evans HDC does not become solid or expand like antifreeze containing water.
Evans also points out that its HDC waterless coolant avoids corrosion and electrolysis between dissimilar metals within the cooling system, and the absence of vapor reduces system pressure. As a result, pump seals last longer, hoses and gaskets will not deteriorate, and costly cylinder liner cavitation erosion can be avoided. Additionally, Evans waterless coolants last the life of the engine so replacement and disposal costs are eliminated.
Ongoing research by industry suppliers has led to more effective coolants. By using the correct type and concentration of antifreeze, along with recommended maintenance practices, the suppliers say, fleets should be able to avoid many cooling system problems and achieve optimum performance levels.
