Summer heat, traffic and long drives push your cooling system to its limits. A quick check now is far cheaper than a warped cylinder head later.

1. Coolant

Check the level when the engine is cold and look at the colour – rusty or sludgy coolant has lost its protection. Use the coolant type specified for your vehicle and flush it at the recommended interval. See coolant.

2. Radiator and cap

Look for leaks, corrosion and bent or blocked fins. A weak radiator cap can drop system pressure and cause boiling. See radiators and caps & thermostats.

3. Hoses and clamps

Squeeze each hose – it should be firm, not soft, cracked or bulging. Replace any that look tired. See hoses.

4. Water pump and belts

A failing water pump may leak, whine or wobble. Replace it with the timing belt if it is driven by one. See water pumps and belts.

5. Fans and thermostat

Make sure the electric fan switches on when the engine is hot, and that the thermostat opens at the right temperature. See fans.

If it overheats

Pull over safely, turn the engine off and let it cool before opening the radiator cap. Never open a hot cooling system – it is under pressure and can cause serious burns.