A Valve Oil Seal is a tiny part that is frequently used in an automobile's internal combustion engine to stop oil leakage into the combustion chamber. It is situated on the valve stem and offers a strong seal all the way around the valve guide to stop oil from getting into the combustion chamber and combusting with the fuel. Typically made of rubber or silicone, Valve Oil Seal is engineered to withstand the high temperatures and pressures of the engine.