Symptoms drivers describe
- Needle rising above the usual midpoint
- Temperature climbing in traffic but settling when moving
- Heater blowing cold while the gauge is high
- Coolant smell or steam from the bonnet
Possible causes
- Low coolant level, often from a small leak
- A stuck thermostat
- A failed cooling fan or fan control fault
- A failing water pump
- Air in the cooling system after previous work
- A blocked radiator or restricted airflow
What you can do
- Turn the heater to hot and full to shed some heat
- Pull over safely and let the engine cool before opening anything
- Never remove a pressurised expansion cap when hot
How we check it in the workshop
We pressure test the system, check the thermostat operation, fan control and pump, and look for combustion gases in the coolant where symptoms suggest it.
Is it safe to keep driving?
Do not keep driving a car that is overheating — head gasket and cylinder head damage can follow quickly.