This ASTM manual has been developed by Committee D-15 on Engine Coolants and is a revision to ASTM Special Technical Publication (STP) 120B. This publication provides consumers with practical information and advice on engine coolants as well as cooling system chemicals, such as cleaning compounds and practices, antirusts, and stop-leaks. This fourth edition presents new information on coolants containing silicates for the protection of aluminum components in today's engines.