Editing Organic Acid Technology (section)

====OAT-based extended-life coolants====
OAT stands for Organic Acid Technology, and includes such ingredients as sebacate, 2-ethylhexanoic acid (2-EHA) and other organic acids, but no silicates or phosphates (except in the case of Toyota's pink extended-life coolant, which adds a dose of phosphate to its extended-life OAT-based antifreeze). OAT-based coolants are usually (but not always) dyed a different colour to distinguish them from traditional blue/ green antifreeze. GM OAT-based Dex-Cool is orange. Volkswagen/Audi uses a similar product that is dyed pink. But Honda has an extended-life OAT coolant that is dyed dark green and does not contain 2-EHA. 

The corrosion inhibitors in OAT coolants are slower acting but much longer-lived than those in traditional coolants. Consequently, OAT coolants typically have longer a recommended service life.

OAT corrosion inhibitors provide excellent long-term protection for aluminium and cast iron, but may not be the best choice for older cooling systems that have copper/brass radiators and heater cores. It depends on the formula.