Keeping your car cool in the winter time sounds like a contradiction, but no matter how cold the temperature is outside, your engine feels the heat while it's running. Removing excess heat from your engine is the one and only job of the cooling system. If this heat is not removed adequately and is allowed to build up, it can spell disaster for your engine. The removal of heat is accomplished by circulating coolant fluid through the engine, which is then passed through the radiator where the heat it carries is transferred to the air moving through the radiator.

Long ago, water was seen as sufficient means to cool an engine. However, water freezes at low temperatures, which is very problematic in a mechanical environment. When water freezes it expands in volume, and if used as a coolant can rupture and damage vital engine parts - a very expensive problem to say the least. With this in mind, modern cooling systems utilize a mixture of water and "anti-freeze" - normally a type of alcohol that allows the mixture to remain liquid below freezing temperatures. Another problem is corrosion - mixing metal and liquid normally results in corrosion taking place, so the coolant also must be formulated to resist it.

It is estimated that 30-40% of engine downtime is a result of an improperly functioning or damaged cooling system, so it is very important to keep the system maintained. Normally this is accomplished by a coolant flush.

A coolant flush involves the old fluid being flushed from the system, cleaning deposits and clearing corrosion and possible contaminates. After the flush process is complete, fresh coolant fluid is placed into the cleaned system. As an alternative, additives can be added to the existing coolant which help restore it's original effectiveness.

There are several different varieties of engine coolant these days, often indicated by color. The classic green coolant is a phosphate and silicate formula, and is present in most vehicles. This coolant should be flushed and replaced every couple of years or 30,000 miles, whichever comes first. Then there is orange coolant which is free of phosphates and silicate, generally regarded as an extended life coolant and is present in many GM vehicles (Dex-Cool is of this variety). There are more colors still, such as red and yellow, created with different formulas and intended for specific uses.

Engine coolant should be checked often, at minimum during your regular service intervals. The cooling system is a vital component for any vehicle, and because it affects so many internal parts of a vehicle, properly maintaining the cooling system greatly lowers the chances of breaking down with far more costly problems down the road.