How To Prevent Overheating Problems

Coolant (a mixture of water and antifreeze) is pumped around the engine, and cools it by means of the radiator. If the level gets too low, it can cause overheating and serious damage. It's normal to have to top it up occasionally, but the need to frequently top-up could mean that there is a leak which needs to be fixed. The coolant should also be renewed at specified intervals - between 2 and 5 years is typical.


You will need the following:


To top up, you'll need some coolant of the right type (check your car's handbook) and some rag, a funnel or jug might also be useful.

Step 1:

Most cars have a coolant reservoir like this. With the engine cold, the coolant level should be betweent the two marks.

Step 2:

If the level's too low, top up using a 50/50 mixture of water and antifreeze (or clean tap water in an emergency, but make up the antifreeze concentration afterwards). Don't overfill.

Step 3:

Refit the cap tightly afterwards and mop up any spillage.

Step 4:

To renew the coolant, open the radiator drain tap (arrowed) or disconnect the bottom hose.

Step 5:

If there is a cylinder block drain plug, unscrew it. Flush the system with clean water, or maybe a flushing compound.

Step 6:

Close the drains and refit any hoses, then refill the system with the correct water / antifreeze mixture.

Step 7:

Some cars have bleed screws which must be opened when refilling to avoid airlocks. Check your Haynes manual for details.