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Three Antifreeze Maintenance Strategies Worth Considering

Posted on April 4, 2015

Antifreeze Maintenance
1. HD Green With SCA: The antifreeze market is moving away from the “old school” of HD green antifreeze with nitrite (DCA2) and or molybdate (DCA4) as the main inhibitors to measure and boost with DCA as needed. HOWEVER, this can be a viable approach for older mixed-fleets where repairs are an issue.

  • What to do: Check nitrite/moly, freeze point, and pH regularly. Add DCA (or spin-on canisters) as required.
  • Beware: Older trucks can leak a lot of antifreeze; have jugs of 50/50 available for the drivers to avoid them buying full-strength or simply adding water out of convenience. (IRSI conventional +)

2. Nitrited OAT: This is generally the current state of many fleets. Several leading antifreeze blends are a combination of inorganic inhibitors, with a fair share of longer-life organic acids. The “wear indicator” is nitrite, which can deplete rapidly.

  • What to do: Check nitrite (dca2) and or moly,(dca4) if applicable, freeze point, and pH regularly. Add DCA2 OR DCA4 extender as required or change filter.
  • Beware: OAT coolants are notorious for “weeping” through small fissures and hose barbs. DEFINITELY keep the proper top-off coolant in the trucks. Many convenience stores and truck stops may not have the right product at a reasonable price, and your driver may be forced to compromise the coolant with substandard product. (IRSI Extended life global +)

3. Nitrite-free Organic (NAP free): This is the future of truck maintenance, according to the visionaries. One antifreeze / coolant fits all, and can last for 750,000 miles.

  • What to do: Check freeze point whenever topping off. Ignore nitrite/moly levels (there are none!). The pH is good down to 6.5! NAP free antifreeze / coolants have significant stop-leak attributes, and you will notice a reduction in coolant loss. Consider marking radiator caps a different color. KEEP NAP FREE FLUID IN THE TRUCKS!
  • Beware: Poly organics can tolerate a fair amount of “foreign” coolant, but it will muddy the color and cause your technicians some concern for their spiffy new age antifreeze / coolant (NAP free). (IRSI poly ultra +)

4. Mixed Strategy: It is possible to sort the fleet into two groups, and act according to each of the above outlines. Problem: how to designate and not confuse anybody.



American Society for Testing and Materials NORA - An Association of Responsible Recyclers Focus on the Family Neighborhood Christian Clinic Reuse and Recycle Fulfleet Antifreeze