The Flywheel Housing Seal, also known as the Rear Main Seal, is a component that seals the gap between the engine block and flywheel housing to prevent oil from leaking out. It is located at the back of the engine and is typically made of rubber or silicone. The part is an essential component in maintaining proper engine function. A damaged or worn Flywheel Housing Seal can lead to oil leaks, reduced engine performance, and potentially costly repairs if left unaddressed.