LO 11-5 Describe and explain the classification, composition, and applications of various antifreeze formulations

1.4. Nitrated and Nitrite/Nitrate Organic Acid Technology

Nitrated and Nitrite/Nitrate Organic Acid Technology
Nitrite/nitrate organic acid technology (NOAT) is similar to HOAT but with additional amounts of nitrates/nitrites added. This chemical combination is expected to make the antifreeze suitable for use in both LD and HD diesel cooling systems, and it is also marketed as a universal antifreeze. NOAT and HOAT are very similar in performance characteristics, but currently no vehicle OEM uses a factory fill of NOAT antifreeze. The normal NOAT service life is 5 years or 150,000 miles (250,000 km) and uses an extender package halfway through the service life.

NOAT is a desirable antifreeze chemistry undergoing refinement to rid the formulation of the aluminum-damaging nitrites and nitrate additives. This coolant chemistry is the only one that is considered to never require draining. Additionally, neither top offs nor testing are required with its use.