Types of Coolants:

Depending on the usage and applications, there are at least 3 types of coolants used in heavy duty vehicle engines. They are as follows

1. Traditional Coolant

These are the regular or conventional coolants having corrosion inhibiting properties that protect the metals such as steel, aluminum and copper from corrosion. In heavy duty engines, this coolant provides excellent protection against wet sleeve liner corrosion. These coolants are typically found in green or purple color. The corrosion inhibitors in the coolant have faster depletion rate and hence a limited lifespan.

2. OAT Coolant

OAT or Organic Acid Technology are silicate free and long life coolants. Unlike the traditional coolants, the carboxylate acid corrosion inhibitors used in them have very low depletion rates. Hence, frequent periodical fueling of Supplemental Coolant Additives is not required and one refill can often be used over the engine’s lifetime. They are typically red or orange in color. It also provides an outstanding protection of aluminum at high temperatures.

3. Hybrid Coolant

This coolant technology combines the benefits offered by traditional corrosion inhibitor technology and combines this with the benefits of OAT corrosion inhibitor technology. This coolant is found typically in yellow and red color. They are used in both light and heavy duty diesel applications. This hybrid technology is also referred to as HOAT technology.