This specification covers the requirements for fully-formulated glycol base coolants for cooling systems of heavy-duty engines. When concentrates are used at 40 to 60 % glycol concentration by volume in water of suitable quality, (see ), or when prediluted glycol base engine coolants (50 volume % minimum) are used without further dilution, they will function effectively during both winter and summer to provide protection against corrosion, cavitation, freezing, and boiling. This specification is intended to cover the requirements for engine coolants prepared from virgin or recycled ethylene or propylene glycol. Committee D15 has not substantially studied the impact of using recycled glycols from sources such as: to prepare engine coolants. However, several serious cases of very poor performance have been reported and substantiated in heavy duty fleets when recycled glycols from sources such as above have been used to prepare engine coolants. Efforts are underway to more clearly define the purity requirements for glycols used to prepare engine coolants meeting this specification, whether from recycled engine coolants or other sources. The coolants governed by this specification are categorized as follows: Coolant concentrates meeting this specification do not require any addition of Supplemental Coolant Additive (SCA) until the first maintenance interval when a maintenance dose of SCA is required to continue protection in certain heavy duty engine cooling systems, particularly those of the wet cylinder liner-in-block design. The SCA additions are defined by and are the primary responsibility of the engine manufacturer or vehicle manufacturer. If they provide no instructions, follow the SCA supplier's instructions. The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.