This Report is intended as a source of information concerning the basic properties of engine coolants which are satisfactory for use in internal combustion engines to provide corrosion protection@ lower the freezing point@ and raise the boiling point. For additional information on engine coolants see SAE J1034 JUL88@ Engine Coolant Concentrate - Ethylene Glycol Type. The values which are presented describe desirable basic properties. The results from laboratory tests are not conclusive@ and it should be recognized that the final selection of satisfactory coolants can be accomplished only after a series of performance tests in vehicles. The report also describes in general terms the maintenance procedures which should be applied to insure a properly functioning cooling system. It is not intended to cover maintenance of engine cooling systems and components which are discussed in detail in SAE HS 40@ maintenance of Automotive Engine Cooling Systems. Heavy-duty non-automotive and heavy-duty diesel engine coolant maintenance may require different measurement and test parameters due to differences in engine design and materials@ and high mileage service requirements.