An oil seal, also known as a shaft seal, is a component designed to prevent the leakage of oil or other fluids from a rotating shaf, is used to prevent lubricant from escaping the engine crankshaft. This type of seal typically consists of a flexible lip that fits tightly around the shaft and is held in place by a metal casing. A properly functioning oil seal helps to maintain optimal engine performance by preventing contamination of internal components with foreign substances, reducing friction between moving parts, and extending the lifespan of critical engine components.