Camshaft Seal
A circular seal that prevents engine oil from leaking from the front or rear of the camshaft.
The camshaft seal is a round rubber gasket pressed into the cylinder head around the end of the camshaft. On engines with overhead camshafts (OHC), the camshaft extends out of the cylinder head to connect to the timing gears or sprockets. The camshaft seal prevents pressurized engine oil from leaking out around the spinning camshaft.
Like other engine seals, camshaft seals degrade over time due to high operating temperatures and friction. A leaking camshaft seal typically allows oil to run down the front or rear of the engine block. If it leaks onto a timing belt, the oil can cause the rubber belt to swell, skip teeth, or fail prematurely, which can cause catastrophic engine damage in interference engines.
Replacing a camshaft seal involves removing the timing belt or timing chain cover, removing the camshaft sprocket, and carefully prying the old seal out without scratching the camshaft or cylinder head surfaces. It is standard maintenance to replace camshaft seals during a timing belt or cylinder head overhaul.