The trend of increased coolant temperature and potential benefits for reduced hydrocarbon emissions from further temperature increases has prompted an investigation of the performance of ethylene glycol base coolant at substantially higher operating temperatures. A coordinated program in laboratory glassware and bench apparatus, in engine dynamometer and vehicle tests has been conducted at bulk liquid temperatures as high as 300°F. In this work it has been shown that suitably inhibited glycol-water coolants can operate for reasonable periods of time and mileage without undergoing undesirable degrees of deterioration while maintaining good heat transfer characteristics and adequate corrosion protection. Further findings of the test program to date indicate that conventional brass-solder radiators, coolant hoses, and clamps may need to be modified to be adequate for temperatures and pressures of future cooling system environments.
