Use only the recommended mixture of good quality anti-freeze and, preferably, rain or other soft water.

Cooling systems generally give little trouble, and often the only time they are given attention is when something goes wrong, such as the temperature gauge showing a high reading - or a pool of coolant appears beneath the vehicle.

Wise motorists follow the recommendations in the appropriate handbook for servicing, correct anti-freeze levels and suggested drain and renewal times.

Okay, let’s look at a few basics: topping-up of the system - which should hardly, if ever, be required - must be done only with the correct anti-freeze/water mixture. Fail to do this and, with repeated topping-up, there will eventually be only plain water or a weak mixture in the system.

Apart from protection against coolant freezing, anti-freeze also guards the internal metal surfaces against corrosion. To maintain such protection, it is recommended that the coolant be renewed every 12 months or so.

Where anti-freeze is not required, a suitable corrosion inhibitor in the coolant is essential.

Water hoses are durable but, especially on vehicles more than a few years old, it is important to check for cracking or other signs of deterioration. Very minor topping up is normally okay, but if in doubt, get the system pressure-tested. In the absence of a pressure test, with the engine hot, any leakage should be apparent anyway.

On cars where no anti-freeze or corrosion inhibitor has been used, there may be no obvious danger signs. Metal pipes corrode and particles of rust cause blockages. If there is some doubt about when the system was last flushed, do it as soon as possible.

To do this, remove the filler caps and open the radiator cylinder block and radiator drain taps.

If there is a plug in the bottom water pipe, remove it and run cold water through a hose into the radiator cap.

You will probably be surprised at the state of the coolant. If it is a nasty brown, remove and preferably renew any metal pipes, and inspect the insides of rubber hoses. A hose that looks okay on the outside could have serious internal deterioration.

Any signs of swelling indicate weakness and renewal is called for.

When the system has been neglected for a long time, back-flushing is recommended. Ideally, when the radiator is suspected of being blocked, remove it from the car and reverse flush by inserting a hose in the radiator’s lower connecting stub with the radiator inverted.

Should the radiator show leakage, while a DIY (Do It Yourself) job is sometimes possible, it is generally best to take the radiator to a specialist. Often you find that, when trying to solder up a leak in a matrix, the heat from the iron causes another leak next to the first one, so a professional job is safer and surer.

Flush the radiator with one of the proprietary cleaning systems.

Then, once the system is clear, use only the recommended mixture of good quality anti-freeze and (preferably) rain or other soft water.

Apart from the radiator and associated pipes, the thermostat, drive belts and cooling fan must also be taken into consideration when an overheating problem occurs. Careful maintenance is necessary if your engine is to keep its cool. Remember that a water loss could wreck the engine. - Star Motoring