Coolant, also called antifreeze, does far more than its name suggests. It stops the engine boiling in summer and freezing in winter, and it protects the metal inside from rust. Using the wrong type can cause real damage.
What coolant does
Mixed with water, coolant raises the boiling point and lowers the freezing point of what circulates through your engine. It also carries corrosion inhibitors that protect the water pump, radiator and passages inside the block.
Do not choose by colour alone
Coolant comes in green, orange, pink, blue and more, but colour is not a reliable guide to the chemistry. What matters is the specification your carmaker lists, such as an IAT, OAT or HOAT type. Mixing incompatible types can turn the coolant to sludge.
How to pick the right one
Check the owner manual or the cap for the required specification, then buy a coolant that meets it. If you are unsure, a universal coolant designed to be compatible with multiple types is a safer bet than guessing by colour.
Frequently asked questions
Can I just add water to the coolant?
In an emergency a little water gets you home, but water alone does not protect against freezing or corrosion, so restore the correct mix soon.
How often should coolant be changed?
Many modern coolants last around five years or 100,000 miles, but check your manual since it varies.
Keeping the engine healthy starts with the right fluids. See our engine and fluid guides.
