This gasket seals the connection between the turbocharger and the exhaust manifold or intake piping on the host engine. It prevents pressurized air and exhaust gas from leaking at the joint, which would reduce boost pressure and alter the air-fuel ratio. A failed gasket produces a whistling noise, a loss of engine power, and can allow unfiltered air to enter the intake stream. The original part matches the sealing face geometry and crush characteristics of the factory assembly, ensuring the clamp load is distributed evenly across the joint. On reinstallation, clean both mating surfaces and replace any locking fasteners if the manufacturer specifies them.