WARNING

The suggestions given on this webpage are for emergency use only. In certain circumstances, using improvised parts to make car repairs can invalidate your car warranty. Do so only as a strictly temporary measure, and when driving conditions in your judgement make such repairs safe.

No coolant. If you haven't checked your coolant level recently you may simply have lost so much coolant through minor leaks and evaporation that insufficient remains to cool the engine.

Faulty water pump. Strange noises from the front of the engine, a total lack of coolant circulation or a severe leak from the pump housing are the tell-tale signs of water pump failure.

Blown head gasket. A breach in the head gasket will allow combustion gases to escape into the cooling system and coolant to enter the engine, seriously affecting both.

Refill the cooling system with any reasonably clean water. But do not pour cold water into a hot engine. If you have a metal water container stand it on the exhaust manifold for a few minutes before topping up the system. Sealed cooling systems must be bled after refilling. This involves undoing any bleed screws or removing the heater radiator return hose and then running the engine with the heater on. Keep topping up the system until bubble free coolant starts coming through, then close the screws or refit the hose.

A split hose can be repaired with tape although a better repair will be made if you use electrical tape over tinfoil and then wrap wire, or fit hose clips, over the repair.

A leaking radiator may be repairable with a dedicated product at auto shops. But depending where the leak is you could try epoxy resin filler, glue or even tapping a wooden bung into the hole.

A jammed thermostat can simply be removed and the car run without it. You may need a little gasket cement to ensure that the thermostat cover seals tightly when refitted.

A blocked radiator can sometimes be cleared with a flushing agent. If this fails, try letting the system cool down and then driving on slowly with the heater on and the thermostat removed — the blockage may only be partial.

A kinked hose can be straightened by either fitting a very stiff piece of wire inside it, or winding fencing wire around the hose to form a spring-like support.

A seized water pump can sometimes be freed by working the pump pulley back and forth by hand. If your pump has a grease nipple try lubricating it, Water pump replacement is not a roadside repair so if it has failed you will have to have your car towed away.

Head gasket failure can be confirmed by allowing the engine to cool and then removing the radiator cap. Making sure no one is standing too close, start and rev the engine. If the gasket has failed, coolant will gush from the radiator. If this fault is confirmed you will have to get the car towed away.