Conventional engine coolant systems use primarily ethylene glycol with inorganic inhibitors. New systems based on organic acids are currently being introduced into the market. The primary advantage of these systems is non-depletion of the inhibitors, allowing extended service intervals, where the coolant is changed between 100,000 - 200,000 miles versus 30,000 - 50,000 miles with the current systems utilizing inorganic inhibitors. This benefits the consumer and the environment.Plastic components are widely used in coolant systems where radiator end tanks, water pump impellers, inlets, outlets, and thermostat housings can be polymeric. A study was conducted in which a number of engineering plastics were exposed to conventional and long life coolants at elevated temperatures and pressures to determine the effect of the coolant. The intent of the study was to provide insight into plastics which can withstand the hot acid environment of extended life coolants during usage. Several extended life coolant systems were investigated, including one containing 100% remanufactured glycol, furthering a more environmental friendly system.