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 pressure sealed cap located on top of the radiator. It allows the cooling system to operate under high pressure for greater efficiency. Always use caution when removing the radiator cap from a warm radiator!