Why Is My Car Overheating?

What to do the moment it overheats

If the temperature gauge heads into the red or a coolant warning light comes on, pull over as soon as it is safe and switch the engine off. Carrying on can warp the cylinder head and turn a cheap fix into an expensive one.

Do not open the coolant cap while the engine is hot. The system is under pressure and hot coolant can spray out. Wait until it has fully cooled before checking the level.

Low coolant and leaks

The most common cause is simply not enough coolant. Look for drips under the car, a sweet smell after driving, or crusty residue around hoses, the radiator and the water pump.

If you keep topping up and cannot see where it is going, the coolant may be leaking inside the engine. That is one of the signs of a head gasket problem, so get it checked rather than keep topping up.

Thermostat, water pump and radiator

The thermostat opens to let coolant flow to the radiator once the engine is warm. If it sticks shut, the engine overheats quickly, often within a few miles. A failing water pump stops coolant circulating properly, and it can leak or make a whining noise as it wears.

A radiator blocked with old scale or clogged with debris at the front cannot shed heat, and the problem gets worse on warm days or long climbs.

Overheating in traffic but fine on the move

If the temperature only rises when you are sat in queues, such as stop-start traffic through Smethwick or Bearwood, the cooling fan is the usual suspect. When you are moving, air flows through the radiator on its own. When you stop, the fan has to do that job.

A fan that is not switching on can be the motor, a fuse or relay, or a sensor, so it is worth testing before replacing parts.

Get it looked at in Smethwick

At ER Automotive we pressure test the cooling system, check the fan and thermostat, and test for exhaust gas in the coolant if a head gasket is suspected, so you only pay for the part that has actually failed. Call 0121 461 6097 or book online.