Engine coolants, antirusts, and antifreezes have certain chemical properties which are useful for their identification and stability measurement. These properties include pH, ash, water content, reserve alkalinity, and chlorides. The ASTM test developed for each chemical property is discussed, highlighting the relative benefits of each. Application to products in the marketplace will include: assisting in developing new formulations, aiding in monitoring inhibitor depletion in corrosion tests, assisting in ensuring high quality production standards, assisting in settling customer complaints, aiding in classifying competitive products and assisting in identifying premium versus low quality antifreeze coolants.