This cylinder head gasket seals the combustion chamber between the engine block and the cylinder head. It prevents the escape of compression gases and the mixing of coolant and oil passages. A failed gasket causes loss of compression, coolant contamination, or oil emulsification. The gasket is manufactured to match the original sealing surface geometry and crush characteristics, which ensures proper clamping force distribution when the head bolts are torqued to specification. On reinstallation, clean both sealing surfaces and replace the gasket; do not reuse.