Valve Springs and valve stem seals are fairly simple therefore damaged ones can be changed without having to bare the cylinder heads and it usually require only two special tools and compressed air source. Start by taking off the valve cover of the cylinder head you suspect to have problems, although if all valve stem seals will be replaced, both covers should be removed. Subsequently, extract one of the spark plugs from the one cylinder with the damaged component and if replacing all the seals, to and remove all of the spark plugs. Adjust the crankshaft until the piston of the cylinder that has been identified to have the issue is positioned at the Top Dead Center at the compression stroke and should begin with cylinder number one and then follow the firing sequence. Insert an adapter into the spark plug hole together put an air hose connected to a compressed air. Depower the valve with the bad section and pull out the pushrod and the associated bolt, fulcrum, and rocker arm. Use compressed air to the cylinder and both valves should remain fixed on the cylinder. Work a rag into the cylinder head holes to keep parts from falling into the engine; to remove the keepers use a valve spring compressor and pull the spring to allow you to remove the keepers with needle nose pliers or magnet. In the event that the air pressure will not close the valve, there is possibility that the face or seat of the valve will be harmed or damaged, where the additional process of pulling the cylinder head will take place. Put a rubber band or tape around the head of the valve stem to ensure that the valve doesn't fall into the combustion chamber, then deflate it. Check the valve stem for sign of wear, it must rotate smoothly and the binding should not be present. Apply pressure on the valve again so they remain closed, finally remove the tape or rubber band that was used. Remove the old rubber guide seal wash the grease from the stem and lubricate it and install a new guide seal in addition to the spring and retainer. Compress the cover of the valve spring and place the keepers in the groove, and put a little grease to prevent the Keepers from falling. Take off the spring tool pressure and the keepers should seat themselves, after which the air hose and the adapter should be disconnected. The rocker arm(s) should be reinstalled, then the push rod(s), spark plug(s) and wire(s) should then be put back on and closed off with the valve cover(s). Open the hood and turn ignitions and examine for signs of oil seepage and any funny noises originating from the top of the engine.
