Oil definition
A substance that lubricates and cools the moving parts of the engine and reduces the formation of rust and corrosion. It contains additives which fights the corrosion of bearings, keeps small particles in suspension, reduces engine wear, and reduces oxidization, minimizes carbon, lacquer , and gum formation. Oil comes in varying viscosity weights suitable for efficient operation in cold and hot weather and for engines in varying states of wear. Also see crude oil , diesel oil , gear oil , viscosity , multi-viscosity oils , and penetrating oil .