Extensive damage occurs in an engine that runs in an overheated state for a prolonged period of time. This is the reason almost all vehicles are equipped with a heat gauge or with a sensor that warns the driver if the engine heat is too high. When an engine overheats, the vehicle needs to be turned off immediately to avoid permanent damage.
Seals and gaskets only are designed to withstand the heat generated in the normal operation of an engine. When the engine overheats, the seals begin to melt, dry out or crack — all of which can cause leaks. Valve stem seals, for instance, crack after an engine overheats. This leads to a variety of oil-related problems, including increased emissions. Performance also may be compromised if oil residue gathers on the spark plugs or around the intake valves.