Glossary

ASTM
ASTM International, formerly known as the American Society for Testing and Materials (ASTM), is a globally recognized leader in the development and delivery of international voluntary consensus standards including those related to engine coolant.

Fully Formulated
A term used to describe a coolant that does not require the “precharge” addition of a Supplemental Coolant Additive prior to installation in heavy duty use. Such coolants are formulated with the needed corrosion inhibitor package suitable for both light duty and heavy duty application.

Glycol
A term used to identify a compound containing two hydroxyl groups. Various glycols exist that when combined with water form aqueous solutions exhibiting beneficial characteristics that are ideally suited for heat transfer fluid functional requirements. Propylene glycol (PG) and Ethylene glycol (EG) are typically encountered with EG being most prevalent for use in engine coolant. 

Heavy Duty
A coolant application generally restricted to commercial vehicles or other severe use in which high stresses and frequent demand are placed on the engine. Typically these engines use diesel fuel.

HOAT
Acronym for Hybrid Organic Acid Technology as used in a coolant corrosion inhibitor package. The package would compromise both inorganic and organic based additives.

IAT
Acronym for Inorganic Additive Technology as used in a coolant corrosion inhibitor package. Typical inorganic additives include silicate, borate, phosphate, nitrate, nitrite and molybdate.

JIS
Acronym for Japanese Industry Standard.

Light Duty
A term used to describe a coolant application generally restricted to passenger vehicles or other engines subjected to lower and infrequent demand.

Nitrite
A specific inorganic corrosion inhibitor offering proven corrosion protection of cast iron and mild steel as typically found in heavy duty diesel engines. Can be used alone or combined with Molybdate for this application.  Some newer coolant technology provides the same corrosion protection without the use of nitrite, referred to as Nitrite-free (NF) coolant.

NOAT
Acronym for Nitrite Organic Acid Technology, a particular coolant corrosion inhibitor package. This type of extended life inhibitor package comprises carboxylic acids and derivatives in addition to nitrite, making it suitable for heavy duty applications. NOAT are required for use with select diesel OEMs that require a nitrite base coolant be used in their engines.

OAT
Acronym for Organic Acid Technology as used in a coolant corrosion inhibitor package. Typically these are based on a variety of carboxylic acids and derivatives.

SAE
SAE International is a global association of engineers and related technical experts whose core competencies include voluntary consensus standards development including those related to engine coolant.

SCA
Acronym for Supplemental Coolant Additive, an aftermarket product typically added to select light duty coolants in order to make them suitable for use in heavy duty applications. This “precharge” is required to impart the necessary inhibitors like Molybdate and/ or Nitrite or to replenish depleted inhibitors in installed coolant as required for heavy duty application. Most SCA use has been supplanted by the introduction of extended life diesel coolants which do not require an SCA.

Silicate
A specific inorganic corrosion inhibitor often used in conventional coolant for aluminum metal protection. High dose loads can lead to formation of precipitates in the coolant and subsequent plugging of radiators.

TMC
Acronym for Technology & Maintenance Council of the American Trucking Associations (ATA), publisher of Recommended Practices (RP) specific to trucking equipment including coolant requirements.