Supplemental Coolant Additives for Maintaining Heavy Duty Coolants

Supplemental Coolant Additives, SCAs, have been a routine ingredient of good conventional coolant programs for many years

Most fleets find that conventional technology coolant, maintained with a quality supplemental coolant additive, proves cost-effective.

SCA products such as Fleetguard DCA-4, Nalcool and Pencool are well known to people who maintain large diesel engines. Before the development of fully-formulated antifreeze, so called "low silicate" antifreeze was blended with water, then an initial "pre-charge" of SCA was mixed in.

This was usually done by adding 1 pint of SCA for every 4 gallons of coolant, but there also exists "pre charge" coolant filters that were installed at a factory to provide the larger, initial dose of additive that the engine required. After the pre-charge, maintenance typically  involved adding a pint of liquid or changing the coolant filter at every oil change.

Since the older systems were large, leaked, and most coolants did not contain nitrite, this was a successful practice. Coolant was also changed every year or two. Some fleets still follow this practice, but more and more fleets are looking to extend coolant drain intervals beyond 2 years.

Today, antifreeze technologies are available that, if properly used, can dramatically reduce the cost of maintaining a cooling system.

For example, purchasing fully formulated coolant costs little more than the old (now obsolete) types of coolant. Fully formulated coolants already contain all the chemistry that the engine requires, so "pre-charging" is a thing of the past. Further, the systems contain less coolant than older vehicles, and they loose less fluid.

Therefore, using fully formulated coolant for initial fill and maintenance (top-up) dramatically reduces the need for SCAs. Indeed, adding SCAs to newer vehicles at every oil fill often results in over-treatment, and some irritating problems have been reported. The best practice is to check the coolant at every oil change, and to add SCA only when levels drop. Time-release and/or Need-Release® filters are also effective. Using these practices, coolant change intervals have been extended in some fleets to 4 or five years.

Traditional SCAs used with fully formulated conventional coolant and a test-to-add maintenance practice, provide one attractive alternative for today's cost-conscious commercial operators.