Why Is Coolant / Antifreeze Different Colours?

14 Mar

Have you ever wondered how pink, orange, blue and green engine coolants differ from each other? Perhaps you’ve bought a car, checked the coolant/antifreeze reservoir for the first time and noticed it was different from your last car.

The colour of engine coolant isn’t there to make it look pretty. There are historical reasons why it comes in different colours, and different brands use different colours as well, but these days it doesn’t necessarily tell you all that much.

However, it’s important to make sure you’re putting the right liquid into your car, so here we give a bit of insight into the differences, and also provide a solution in case you’re confused about which type of coolant/antifreeze to use or worried about what’s in your car.

In days gone by, the colour of coolant was determined by the type of chemicals used to prevent corrosion — meaning you could tell a lot about the type of coolant used by its colour. Older coolants that used Inorganic Additive Technology (IAT) were usually blue or green in colour. With these types of coolants, you’d normally have to change them every two years, or every 60,000 km

Next came Organic Acid Technology (OAT) coolants, whose chemical make-up offered better protection for cooling systems, and extended the life of the coolant. These ‘Extended Life Coolants’ (ELC), were usually orange in colour and offered a five-year or 100,000-km change interval. They could be a blend of IAT and OAT chemicals, and were therefore named ‘Hybrids’.

Newer coolants , based solely on the OAT chemical make-up, now offer a 10-year or 150,000 km change interval thanks to their superior corrosion protection. many coolant manufacturers use different colours.