Five different engine tests utilizing nonaqueous propylene glycol as the engine coolant were run to examine various aspects of durability and engine performance. This paper reports the results of these engine and bench tests designed to quantify the effects on performance and engine durability. Comparisons are made to baseline engine tests using 50 % aqueous ethylene glycol coolant. Also reported are the data necessary to determine the effects on the size and design of related heat exchangers.Based on these test results, some of the presumed advantages and disadvantages of the use of non-aqueous propylene glycol engine coolants (1) * have been quantified. This work is useful as a basis for further work using total-vehicle systems taking advantage of this innovative technology.