Valve Cover Gasket
A rubber or cork seal compressed between the engine's cylinder head and the valve cover to prevent engine oil from leaking out of the valvetrain area.
The valve cover gasket is a pliable seal that runs along the perimeter of the cylinder head, forming an oil-tight barrier beneath the valve cover (rocker cover). Its job is to keep engine oil contained within the upper cylinder head, where it lubricates the camshafts, rocker arms, and valves.
Because valve cover gaskets are subjected to high engine temperatures and oil exposure, the rubber eventually hardens, becomes brittle, and cracks. This leads to oil leaks, which can drip onto hot exhaust manifolds (producing a burning oil smell and smoke), pool in spark plug wells (causing engine misfires), or run down the engine block.
Replacing a leaking valve cover gasket involves removing the valve cover, cleaning the mating surfaces, and installing a new pre-formed gasket. It is an essential service to prevent oil loss and engine fires.