When to change your engine coolant

Coolant carries heat away from the engine and stops it freezing in winter. It also contains additives that protect the engine from corrosion, and they wear out over time.

How often

It depends on the coolant type. Many cars want the first change at around 5 years or 60,000 to 100,000 miles (100,000 to 160,000 km), then every 3 to 5 years. Long-life coolants can go longer. Check your manual.

How to check the level

Wait until the engine is completely cold.
Find the see-through coolant reservoir under the hood.
The level should be between the MIN and MAX marks.
Never open the radiator cap on a hot engine.

Signs of a problem

The temperature gauge runs higher than usual.
A sweet smell, or puddles of green, pink or orange liquid under the car.
The low coolant light comes on.
The heater blows cold air when the engine is warm.

Safety

Coolant is poisonous and tastes sweet, so keep it away from children and pets, and clean up spills.

Common questions

Can I mix different coolants?

It’s best not to. Different types can react and form sludge. Use the type listed in your manual.

Can I top up with water?

In an emergency, yes, but it dilutes the coolant. Have the mix checked and corrected soon.

General guidance, not professional advice. Intervals are typical ranges and vary by car, so check your owner’s manual and ask a qualified mechanic if you’re unsure.