This SAE Recommended Practice is applicable to oil-to-water oil coolers installed on mobile or stationary equipment. Such oil coolers may be used for the purpose of cooling automatic transmission fluid, hydraulic system oil, retarder system fluid, etc. This document outlines the methods of procuring the test data to determine the operating characteristics of the oil cooling system and the interpretation of the results. For information regarding application testing of oil-to-air oil coolers for heat transfer performance, see SAE J1468.