So what does the cooling system do? Well, basically it does what its name implies. It cools the engine. It does this by circulating coolant or air throughout the engine block depending on the system used. The most common and reliable system would be the liquid designed system. Coolant is circulated throughout the engine block by means of a pump, tubing, passage ways, and hoses. The coolant is a mixture of 50% coolant, 50% water. The heat from the engine is absorbed by the water and the heat is then the water is cooled by the air moving through the radiator fins. The most common problem with cooling systems is overheating. "Duh!!!" Well, actually, a cooling system can have just the opposite problem as well. Overcooling is also a problem, but first we go over overheating.
Overheating can be caused by a variety of things. It can range from poor engine performance to a blown head gasket. But the most common problem involved with the cooling system components is probably the radiator. Cracks or leaks in the radiator can cause the cooling system to overheat and create engine damage. Cracked or leaking radiators should be replaced immediately! At the same time, the radiator cap should be replaced as well, because the cap not only covers the radiator spout but keeps the system under the correct pressure.
Another problem involving the cooling system would be the water pump. Bearing failure can occur, but can be detected by a leaking water pump or an annoying squeal. However, the impeller on the water pump can also corrode. Water pumps use blades called impellers to circulate the coolant/water mixture. With time these impellers can corrode making the bearings still good, but the pump useless. A few imports, which I won't mention....*cough* Nissan, have a tendency for the impellers to corrode severely. A water pump on timing belt equipped engines should be replaced every time the timing belt is replaced, especially if it is driven by the timing belt. Why? Because if your changing your timing belt (every 60,000 miles) then you might as well have the water pump changed seeing that it will save you time and money in the future. In order to change a water pump separately, the timing belt must be removed anyway if it drives the pump.
A third problem would be leaks. Leaking hoses and pipes should be replaced immediately. A worn hose will either become soft and mushy or hard as rock leaving a potential for a burst.
The last problem I will mention would be the thermostat. It open and closes within your engine and allows the coolant to flow properly. It keeps the warm coolant in the engine till a certain temp is reached then it is opened and the coolant is allowed to flow. If it gets stucked in the closed position, it can cause overheating. However, you may ask why have a thermostat? Why not allow the coolant to flow freely? Well, there are two reasons. The first reason is fuel economy. When the engine is cold, it runs at a higher rpm to heat up the block for fuel efficiency reasons. By keeping the warm coolant in the engine longer, the engine heats up quickly, and reduces the amount of time needed to heat it up. Once the engine reaches a certain point, the engines idle goes down. Over cooling usually occurs when the thermostat gets stuck in the open position. This allows the coolant to constantly flow, and the engine takes a longer time to heat up. Why heat up the engine? A warm engine runs better and gets better performance.economy than a cold one. Secondly, removing the thermostat (as many racers may do) can cause emission control damage.
Disclaimer: I take absolutley no responsibility as far as what you do on your vehicle and any personal harm or vehicle damage that may be the result of your work . What you do is entirely by your choice and judgement.This section is merely for educational and entertainment purposes only. Sorry, but I gotta post this Disclaimer