Short answer: Pull over safely as soon as you can, switch the engine off and let it cool. Do not open the radiator or coolant cap while the engine is hot, because the system is under pressure. Driving on while overheating can badly damage the engine, so call a workshop or a tow rather than carrying on.
What should you do first if the temperature gauge climbs?
Find a safe place to stop, switch the engine off and put the hazard lights on. Leave the bonnet closed for a few minutes, then open it only to let the heat escape. Do not touch the radiator cap or the coolant reservoir cap while the engine is hot, because hot coolant can spray out under pressure.
Should you keep driving to the workshop?
No. An engine that is overheating can be damaged quickly, and the repair can become much larger. If the gauge is in the red or a warning light is on, stop and let the engine cool, then ask a workshop or a tow service for help. If the gauge only rises a little in a long queue, mention it to a workshop soon, because it is still a sign that something needs checking.
What are the common causes of an overheating car?
Low coolant from a leak, a radiator that is blocked or leaking, a radiator fan that does not run, a thermostat that sticks closed, a split hose, a weak radiator cap or a failing water pump. A worn drive belt can also stop the water pump from turning. Less often, a problem inside the engine, such as a damaged head gasket, causes overheating.
Can you top up the coolant and carry on?
Only as a short-term step, and only once the engine is fully cold. Coolant does not disappear by itself, so a falling level points to a leak or a deeper problem. Use the coolant type in your owner's manual, and have the cause found soon. Topping up with plain water is not a fix.
What clues help a workshop find the cause?
Tell the workshop when it happens: in slow traffic, soon after a cold start, at speed or only with the aircon on. Mention any coolant smell, steam, drips under the car, a sweet smell, a falling coolant level or a heater that blows cold. These clues often point to the fan, thermostat, a leak or the water pump.
How can you help prevent overheating?
Check the coolant level when the engine is cold, look for drips or stains under the car, and have the cooling system inspected at your regular service. Do not ignore a gauge that reads higher than usual. Keep to the service schedule in your owner's manual.
What the workshop checks
We start with the coolant level and condition, then look at the hoses, radiator, cap, fan operation, thermostat, water pump and drive belt. A pressure test and a scan for fault codes help to confirm the cause before any parts are replaced. See our engine repair and overhaul service for engine-level faults.
Common questions
What should I do if my car is overheating?
Pull over safely, switch the engine off and let it cool. Do not open the radiator or coolant cap while it is hot. Then call a workshop or a tow service rather than driving on.
Is it safe to drive an overheating car?
No. Driving while the engine is overheating can cause serious engine damage. Stop safely and let it cool first.
What causes a car to overheat?
Common causes are low coolant from a leak, a blocked or leaking radiator, a radiator fan that does not run, a stuck thermostat, a split hose, a weak radiator cap or a failing water pump.
Can I add water instead of coolant?
Water is not a fix. Top up only when the engine is cold and use the coolant type in your owner's manual, then have the cause of the loss found.
Why does my car only overheat in traffic?
It can point to a radiator fan that is not running, because there is less air flow when the car is moving slowly. A workshop can check the fan and the rest of the cooling system.
