Haynes seriously useful info

The Seriously useful info series

Although many car owners believe that modern cars are too complicated for them to work on, this is not so. Routine tasks can be done by anybody - if they know what they are doing.

With the Seriously Useful Info series, our mission is to give you a greater understanding of your car and provide you with essential tips, advice and tasks that will aid trouble-free motoring. For example: how to check tyres and engine fluids, replace wiper blades, light bulbs and spark plugs, how to conduct a pre-MOT test check and what to do before taking your car on holiday or abroad.

Links to the other Seriously Useful Info features appear at the bottom of this page.

There's no need to get overheated

Avoid getting overheated Traffic congestion is often a feature of holiday journeys. You shuffle along in a queue of vehicles as the sun beats down - mile after mile at a crawl. Then it happens - the engine boils over and suddenly you’re in holiday hell.

Modern cars are very advanced but they still rely on some basic principles. Water is still pumped around the engine and the heat it collects is dissipated through a radiator - which is cooled by the air flowing through it when the car is on the move. When the car is stationary or moving slowly, an electric fan operates automatically to draw air through the radiator. But if the system is not operating perfectly, it will fail at the worst possible moment so that both you and the engine become overheated.

However, doing a few simple checks before you set off on that long holiday journey should mean your engine stays cool - and so do you.

Haynes, the world-leading publisher of automotive repair manuals, is renowned for teaching millions of car owners how to carry out precautionary checks such as these as well as routine maintenance and repairs. The manuals provide authoritative and accurate step-by step information for both basic and more complex tasks. They also tell you what tools you may need and which products are compatible with your make of car.

For more advice on model-specific procedures, please refer to the appropriate Haynes Service and Repair Manual. Haynes Manuals are available from this website and all good car accessory retailers and bookshops including: Halfords, Motor World and WH Smith. Please use our comprehensive Stockist Locator in the left margin of this page.

Haynes' essential checks to avoid overheating

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.
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.
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.
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.
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...

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.
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.
When applicable, check that the water pump drivebelt is not broken or slack.
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.

Happy motoring!

Seriously useful info features....

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