Oil loss - Radial seals

Radial oil seals are used to contain the oil at the end of the rotating shafts, such as the crankshaft and the camshaft. A stainless steel spring in the seal lip ensures a tight fit around the rotating shaft.

Oil Radial Seals
Oil Radial Seals

The spring ensures a constant leak-tightness around the shaft. Oil loss at the spring seal lip can be due to the shaft not being completely round in which case the crankshaft can be reworked with a shaft sleeve. Oil loss at spring seal lip can also occur due to excessive oil pressure in the crankcase which the spring cannot with stand. Finally any scoring of the shaft around the oil seal running surface can also result in oil leakage.

Oil Radial Seal Cutout
Oil Radial Seal Cutout

Oil loss at the outer edge usually occurs due to incorrect fitting (damaged to outer edge) or general wear and tear. Dirt and high heat can result in premature wear. When replacing faulty oil radial seals, lightly coat outer and inner edge of the seal with oil to ensure that no damage occurs when installing them.