In the engine, the gasket is placed between the cylinder head and cylinder block to prevent leakage, to ensure metallic tight fit joint and also to maintain compression in the cylinder. The gasket should be able to withstand the high pressure and extreme temperature.
The head gasket is compressed between the engine block and the cylinder head. The head gasket seals in the internal combustion process and also keeps coolant and oil from mixing together as the two fluids travel from the engine block to the cylinder head.