A Comparison of Various Polymers in Select Organic Acid Technology (Oat) Coolants

With the introduction of Organic Acid Technology (OAT) coolants into the automobile and truck markets, it has become necessary to perform elastomer compatibility studies to insure that seal materials will withstand the new fluids. This paper will compare Silicone, EPDM, Hydrogenated Nitrile Rubber, and Fluoroelastomer rubber compound formulations in a conventional coolant and OAT coolants with varying additive packages, Benzoic Acid, 2-ethylhexanoic, 2 mono acids (proprietary), and a Hybrid (European) coolant. Standard bench tests, following ASTM D471 immersion, were used to conduct the evaluations. High temperature, 150°C, a standard specification test temperature, 125°C, and a typical operating vehicle temperature, 110°C was used to measure the effects of high temperature acceleration testing on the elastomers as well as the coolants.