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Automatic equipment based on optical detection has been used for petroleum products successfully. Examples include ASTM D5773 Standard Test Method for Cloud Point Determination of Petroleum Products and ASTM D5972 Standard Test Method for the Freezing Point of Aviation Fuels. Recently it has been shown that the technology can be extended to engine coolants1. The determination of freezing point in aqueous ethylene glycol based systems is imperfectly understood and complicated by non-equilibrium solidification. The current ASTM D 1177-94 method includes manual seeding to overcome this but requires a cryogenic bath, time and considerable operator skill. Experimentally determined aqueous ethylene glycol freezing points show good agreement between laboratories only to approximately 60 wt %. In the 58 wt % to 80 wt % region, one, two and even three eutectics have been reported at varying temperatures.

The development of a laboratory test for cavitation erosion corrosion of aluminum pumps with engine coolants is described. It is based on the standard ASTM D2809 test stand but incorporates the pump and cover from a Chrysler 5.9l (360 cu. in.) engine. Operating conditions are varied to simulate components taken from vehicle service. Light duty vehicle service results, obtained in the Colorado Rocky Mountains, for three types of coolant technology with the test pump are presented. Field results include large variations in cavitation protection. Included were two organic acid (OA) coolants, a traditional North American silicate and a European OA silicate hybrid. Comparisons are drawn with the standard ASTM D2809 test, additional components are presented and corrosion morphology discussed.