GM 88891774 Intake Valve Seal

Looseness of valve springs and damaged valves stem seal can be remedied without having to take off the cylinder head; it requires only two special tools and a compressed air. If compressed air is not available a piece of nylon rope can be used to keep the valves from falling into the cylinder. To start, one will have to take off the valve cover and the spark plug from the side of the cylinder which is affected or all spark plugs if changing all valve stem seals. When the piston is at the TDC on the compression stroke turn the crankshaft and using an adapter attach an air hose from a pressurized air source to the spark plug hole. Take off the nut, pivot ball and rocker arm in respect of the defective valve to have the valves compressed by applying some air pressure. In case of air pressure failure, valve job may be required. A worse solution is to partially insert the piston in front of the TDC, through the intake valve, stuff nylon ropes into the combustion chamber, and start to turn the crankshaft until some resistance is met. It is advisable to use shop rags so that the parts will not fall into the engine, and then compress the valve spring using valve spring compressor and remove keepers. After that, unscrew the spring retainer and the valve spring, and then examine the stem to determine if it is worn out, and if the stem can move smoothly within the guide. Pressurise the air to lock the valve back in place, then grease the stem of the valve, and replace the valve guide seal. Position the spring and retainer, then compress the spring to put the keepers on, if grease is needed it should be applied at this stage. Turn off the air hose, take off the adapter and the return of the rocker arms and the pushrods and put the spark plugs and the valve cover back on. Last of all, switch on the engine and observe areas such as the oil drips and abnormal sounds.