DriverSide's Car Dictionary has the most comprehensive definitions of automotive terms. This auto glossary can help you decipher what your mechanic is fixing and what the purpose or function of the particular auto part or accessory is for. We have taken the mystery out of automotive service jargon, so that you don't have to.
A slapping noise in the engine caused by piston wear. This sometimes happens when engines are cold, and can go away when the engine warms, the metal expands, and tolerances between parts change.