This valve cover gasket seals the joint between the valve cover and the cylinder head on the host engine. It prevents oil leakage and keeps contaminants out of the valvetrain area. A compromised gasket allows oil to weep onto the exhaust manifold, producing smoke and reducing oil level. This original AGCO gasket is molded to the same profile as the original sealing surface, so it compresses evenly under the cover bolts without requiring additional sealant. On reinstallation, clean both mating surfaces and tighten the cover bolts in the sequence and to the torque specified for the engine.