1.1 ,This specification covers the requirements for fully-formulated glycerin base coolants for cooling systems of heavy-duty engines. When concentrates are used at 40 to 60 % glycerin concentration by volume in water of suitable quality (see Appendix X1), or when prediluted glycerin base engine coolants (50 volume % min) are used without further dilution, they will function effectively during both winter and summer to provide protection against corrosion, cavitation, freezing, and boiling.