My car is overheating. What should I do?
Pull over safely, switch the engine off and wait. Opening the radiator cap while it is hot can cause serious burns.
What to do straight away
- Turn the heater on full. It pulls heat out of the engine and can buy you a few moments to reach a safe place.
- Pull over and turn the engine off.
- Don't open the bonnet if you can see steam. Wait until it stops.
- Don't open the radiator cap or coolant bottle while the engine is hot. The system is under pressure and can spray scalding liquid.
Once the engine has cooled
- Check the coolant level in the overflow bottle. Top up with the coolant your car's manual specifies, or water in an emergency.
- Look for puddles under the car, hoses that look split, or a cooling fan that never runs.
- If the level was low and you topped up, drive carefully to a workshop and watch the temperature gauge.
Common causes
- Low coolant from a leak
- A stuck thermostat
- A failed water pump or radiator fan
- A blocked radiator
- A blown head gasket, which is the expensive one
Don't push on
Driving an overheated engine can warp the cylinder head and wreck the engine. If it overheats again, stop and arrange a tow. Our Engine temperature warning light page explains the dash symbol. For tow numbers, see Find a shop.
Questions drivers ask
Is it safe to drive an overheating car?
No. Even a short distance can cause serious damage. Stop, let it cool and get advice.
Can I use water instead of coolant?
In an emergency water will get you to a workshop, but it dilutes coolant and lowers its protection, so have the system topped up and checked properly.
Why does my car overheat only in traffic?
Often a cooling fan that isn't working, because there is less airflow when you are slow or stopped. Get the fan and thermostat checked.
Checked by AutoPlace editorial team. General information, not professional advice. Updated 15 October 2026.