There's no need to get overheated

For more advice on model-specific procedures, please refer to the appropriate Haynes Service and Repair Manual. Haynes Manuals retail at £17.99 (hardback) and are available from all good car accessory retailers and bookshops including: Halfords, Motor World and WH Smith. A comprehensive stockist locator can be found at www.haynes.co.uk.

Notes to Editors:

The information above is supplied courtesy of Haynes Publishing, please credit accordingly if you intend to use it. For further information, please contact Rebecca Nicholls on Tel: 01452 260063 or email: pr@haynes.co.uk

Haynes' essential checks to avoid overheating

1. Most modern cars have a coolant reservoir with MAX and MIN markings. With the engine cold, the level in the reservoir should be between these markings. Get into the habit of checking this weekly - the need for frequent topping up suggests a leak in the system.
2. To top up the system, unscrew the reservoir cap slowly when the engine is cold and allow any pressure to escape. (If you do this when the engine is hot, there is a danger of scalding.) Fill to the MAX line (but not above) with a 50/50 mixture of water and antifreeze. Refit the cap tightly and wipe away any spillage.
3. For topping up, always use antifreeze suitable for your make of car - check the information in your Haynes Service and Repair Manual - and mix it with water. In an emergency, plain water will do but remember it will dilute the antifreeze mixture in the system and thus reduce the effectiveness of the corrosion inhibitors. The percentage of antifreeze in the system should be checked before the winter (by a garage or with a simple tester available from car accessory shops) and the coolant should be changed every two or three years.
4. On cars where the water pump is driven by an auxiliary drivebelt (‘fanbelt’), make sure that this belt is in good condition and correctly tensioned.  See your Haynes manual for details.
5. Note that badges or auxiliary lights mounted ahead of the radiator can restrict the airflow and may lead to overheating. Towing a caravan makes the engine work harder and this too can lead to overheating.

And if the engine does overheat...

6. If you are stuck in a traffic jam, keep an eye on the engine temperature gauge. Before it gets into the red, the electric engine cooling fan should come on automatically. If the engine does start to overheat, put the heater on full (maximum heat, highest blower speed) to disperse some heat. Pull over in a safe place and switch the engine off.
7. Check if something is blocking the airflow to the radiator - such as a plastic bag. Lift the bonnet cautiously (beware, the electric cooling fan may still be running) and see if there is steam escaping from a split in a hose or a hole in the radiator. A leaking coolant hose could be secured temporarily with a hose bandage. This will get you out of trouble until a new hose can be fitted. A leaking radiator will have to be replaced eventually, but adding a leak-sealing compound to the coolant reservoir will sometimes fix it for a while.
8. When applicable, check that the water pump drivebelt is not broken or slack.
9. Wait for the engine to cool down before carrying out any repairs or checking the coolant level. Top it up as necessary and proceed cautiously - keeping an eye on the engine temperature gauge.