Valve Seals
There are different types of valve seals found in today's cylinder heads. Aluminum heads will typically use positive lock valve seals. These are the preferred seal these days. These seals are installed prior to the valve and an installation tool is required. This is because these seals snap in place into a machined groove in the head. The intake and exhaust seals are often different sizes and colors.
Another popular seal is the umbrella type valve seal. These valve seals used to be everywhere. They where used on all different types of engines. These seals are installed after the valve has been placed in its guide. Polish the valve with crocus cloth and lubricate it with oil or assembly lube before installation.
O-ring seals are located on the valve stem, the third groove down under the two retainer grooves. They are installed after the valve spring has been compressed. It's important to lubricate the seal with oil before sliding it over the valve stem.
Valve Seal Symptoms: When valve seals leak oil will enter the combustion chamber and the vehicle will emit blue-gray smoke from its tailpipe. This will be most apparent at start up after the vehicle has been sitting for a while. This is because the oil on top of the cylinder head has had time to seep into the chamber. Once this oil has cleared out the smoke may not be so apparent until the vehicle is allowed to sit and be started again.
