Engine Temperature Warning Light
The engine coolant is too hot, or the coolant level is too low to cool the engine.
Critical risk
Stop as soon as it is safe and switch the engine off. Never open a hot cooling system: the coolant is under pressure and can scald.
Short answer · What do I do if the engine temperature light comes on?
Pull over safely and switch the engine off to stop overheating. Let it cool for at least 30 minutes before checking the coolant level in the expansion tank, never opening the cap while hot. If the level is low, top up with the correct coolant; if it keeps overheating, have the car recovered.
What to do
- Stop and switch offContinuing to drive an overheating engine can warp the cylinder head and blow the head gasket.
- Let it coolWait at least 30 minutes. Keep clear of steam.Hot coolant under pressure causes serious burns.
- Check the coolant levelWhen cold, check the expansion tank against the MIN mark and look for leaks under the car.
- Get the cause foundOverheating with a correct level points to a thermostat, fan, water pump or head gasket problem.
How is the light behaving?
| What you see | What it usually means | What to do |
|---|---|---|
| Steady | Coolant is overheating or the level is low | Stop safely and switch the engine off |
| Flashing | Temperature very high on some cars | Stop immediately where it is safe |
| On for a few seconds at start-up | Normal check at start-up | Nothing |
Possible causes
- Low coolant levelLeaks from hoses, radiator, water pump or a head gasket.
- Radiator fan not workingOverheating happens mostly in traffic or at idle.
- Stuck thermostatCoolant cannot reach the radiator.
- Failed water pumpCoolant does not circulate.
- Head gasket failureExhaust gas enters the cooling system.
Don't confuse it with
Questions about Engine Temperature Warning Light
Can I add water instead of coolant?
In an emergency clean water gets you to a workshop, but the mixture must then be corrected: water alone gives no frost or corrosion protection.
Why is there a blue or red temperature symbol?
Some cars show a blue symbol while the engine is cold and red when it is too hot. Blue only means drive gently until warm.