- Corrosion Inhibitors based on fully neutralized organic acids and azoles
- Typically amber, orange or red in color
- Designed for use in automotive, light duty and heavy duty diesel applications
- Silicate free, avoids silicate gelation and related fallout issues
- Amine, borate, nitrite and silicate free meeting the basic chemistry requirements of Asian OEM’s
- Phosphate free, meeting some basic chemistry requirements of European and some North American OEM’s
- Excellent high temperature aluminum protection
- Can provide wet sleeve liner cavitation protection without the use of nitrite
- Extended life in both light and heavy duty applications
- Lifespan: Automotive - Up to 5 years or 250,000 km (150,000 miles); Heavy Duty - Up to 6 years or 960,000 km (600,000 miles)
OAT is an acronym for Organic Acid (Additive) Technology which describes the type of materials responsible for the corrosion protection offered by a coolant of this type. OATs are Long Life Coolants (LLC), based on minimally depleting Carboxylate Technology. This technology provides superior protection to all components of the cooling system including those exotic materials like aluminum and magnesium found in the modern day engine. Unlike Traditional Coolants the need for regular additions of Supplemental Coolant Additives (SCA’s) at scheduled service intervals is no longer required, providing a true Long Life product which can provide significant “cost savings”. In some heavy duty diesel applications you may see a reference to a Coolant Extender. A Coolant Extender can be used with an OAT coolant to top-up certain additives at the products half life which is typically around 480,000 kms. In general OAT based corrosion inhibitors are recognized for their non-toxic properties making them readily biodegradable, addressing any environmental and occupational health & safety issues.
First generation OATs were specific to automotive applications. This was quickly followed by use in heavy duty diesel applications where the OAT was used as is (as in Asia and Europe) or in North America where the OAT was used along with nitrite or nitrite and molybdate to ensure adequate wet sleeve liner cavitation protection.
As a result of work initiated by John Deere there is now an industry specification for determining the liner cavitation properties of Engine Coolant. An ASTM Standard, D7583 is now available which validates the liner cavitation of any engine coolant even those that do not contain nitrite or nitrite and molybdate. Recently, ASTM D15 modified ASTM D6210 to include this liner cavitation test. A review of ASTM D6210-10 will show that nitrite free OAT engine coolants which pass ASTM D7583 are OK for use in heavy duty diesel applications.