Heavy Duty Diesel Antifreeze / Engine Coolant

Heavy Duty Coolant Colors

There are at least five major advanced heavy duty coolant technologies on the market.

antifreeze colors

In the photo on the right, heavy duty coolants are pictured. At the 1:00 position the red-orange coolant is Caterpillar ELC, moving clockwise, the pink is Freightliner FleetCharge®, the Green is Peterbilt factory fill from Valvoline, the blue is Cummins / Fleetguard Compleat®, and finally the yellow is Ford G-05.

Diesel engine coolants are formulated for longer and more severe operation than coolants intended for light duty engines (of course these new technology coolants can be used in light and medium duty vehicles as well).

Heavy duty diesel, and some light and medium duty diesel engines, are exposed to cavitation erosion problems, as well as the problems shared by all engines such as corrosion and water pump durability.

Years ago, ASTM developed a specification, ASTM D4985, for low silicate engine coolant for heavy duty diesel engines that requires a pre-charge of SCA before use. This coolant, maintained properly, provided serve of 240,000 miles or two years. Some fleets still use this type of coolant but it is no longer acceptable to most diesel engine manufacturers

The most current ASTM heavy duty coolant specification is ASTM D6210, an ethylene glycol specification, and ASTM D6211, a similar specification for propylene glycol coolants. These types of coolants are known as "fully formulated" coolants. They contain all of the necessary chemicals required by diesel engines.

Coolants of this type can be maintained with SCA in a test-to-add program. Low TDS fully formulated coolants may contain conventional, carboxylate or hybrid inhibitor technologies. They are maintained in different ways, but all of them should be monitored at every PM interval to at least insure that an approximate 50% antifreeze concentration is present.

Conventional products should also be checked for nitrite or, depending on the brand, nitrite and molybdate concentrations. Extended service coolants also require maintenance but the requirements vary by technology and engine manufacturer.

Conventional fully formulated coolant is the factory fill at most manufacturers, fully formulated carboxylate coolant is standard at International and Caterpillar. Ford trucks come with fully formulated G-05 hybrid coolant.