This gasket seals the joint between the timing cover and the engine block. It prevents oil leakage from the timing gear cavity and keeps contaminants out of the rotating assembly. A degraded or incorrectly seated gasket allows oil to weep onto the front of the engine, which can lead to belt contamination and reduced accessory drive grip. The gasket matches the original profile to maintain the correct clamping force across the cover flange. On reinstallation, clean both sealing surfaces and apply the manufacturer’s specified torque sequence to the cover bolts.