1.1 ,This specification covers the requirements for 1,3 propanediol base engine coolants used in automobiles or other light-duty service cooling systems. When concentrates are used at 40 ,% to 70 % concentration by volume in water, or when prediluted glycol base engine coolants (50 volume % minimum) are used without further dilution, they will function effectively to provide protection against freezing, boiling, and corrosion.