Vehicle engines and all the connecting parts operate within a very specific temperature window. Normally, the engine coolant is more than enough to keep the engine where it needs to be, but sometimes the engine looses coolant and overheats. This is a very nasty situation and can have dire consequences for your car.
One of the common risks of overheating is the detonating or fuel prior to the spark plug going off. Precise engine calibrations cause the fuel to ignite at exactly the right time. Overheating causes hot spots in the cylinders which can ignite the fuel at erratic times. This causes rod knock and very rough running. Enough rod knock can destroy cylinder walls and potentially break a rod.
The metal in your engine block and the metal in your engine head will expand at different rates when heated. Overheating will cause one to expand much farther and more rapidly than the other. The result is a damaged or destroyed head gasket. This can lead to serious problems with oil leaks and cause significant damage to very important parts of the engine.
Overheating also causes your coolant to boil. This liquid mixture can become ridiculously hot and destroy coolant hoses and fixtures. It can even cause them to blow off their fixtures and damage other parts of the engine bay. In more extreme situations or on older cars, the increased pressure can damage the radiator.
