This crankshaft oil seal prevents engine oil from leaking past the crankshaft at the front or rear of the block. It sits in the housing bore and rides on the rotating shaft, maintaining a fluid-tight barrier that keeps oil inside the crankcase and contaminants out. A worn seal allows oil to weep or drip, which can lead to low oil pressure and contamination of the clutch or belt system. This replacement part from Bepco is machined to match the original seal's bore fit and shaft contact surface, so it seats correctly in the housing without modification. On installation, ensure the sealing lip faces the oil side and the bore is clean and free of burrs.