The methods presented in this SAE Recommended Practice apply to the controlled testing of low-temperature charge, air-cooled, heavy-duty diesel engines. This document encompasses the following main sections: a Definitions of pertinent parameters b Vehicle testing to determine typical values for these parameters c Description of the setup and operation of the test cell system d Validation testing of the test cell system While not covered in this document, computer modeling of the vehicle engine cooler system is recognized as a valid tool to determine cooler system performance and could be utilized to supplement the testing described. However, adequate in-vehicle testing should be performed to validate the model before it is used for the purposes outlined. The procedure makes references to test cycles that are prescribed by the United States Environmental Protection Agency (US EPA) and are contained in the Code of Federal Regulations.