Replacing Valve Stem Seals and Valve Springs with Retainers

PROCEDURE


Broken valve springs and worn valve stem seals can be replaced without removing the cylinder head. Only two special tools and a source of compressed air are required. Before starting the work, make sure you have a sufficiently powerful tool for compressing the stiff valve springs used on the engines of these vehicle models.
1. Remove the cylinder head cover (see Section Cylinder Head Cover Removal and Installation).
2. Remove the spark plugs from the cylinders being serviced. If the valve stem seals need to be replaced, remove all spark plugs.
3. Rotate the crankshaft to bring the corresponding piston to top dead center (TDC) on the compression stroke (see Section Positioning No. 1 Piston at Top Dead Center (TDC)). When replacing valve stem seals, start with cylinder No. 1 and proceed to the others in firing order (see Specifications).
4. Remove the rocker arm shaft assembly (see Section Removal, Inspection and Installation of Rocker Arm Assembly).

5. Screw a long adapter into the spark plug hole of the corresponding cylinder and connect a hose from the compressed air source to it. Note: Special threaded adapters with a quick-connect fitting are available - ask at auto parts stores.

6. Apply air pressure to the cylinder.

Under air pressure the piston may move down, causing the crankshaft to rotate suddenly. Do not leave the socket wrench used to bring the piston to TDC on the bolt threaded into the crankshaft pulley. The valves will be held in place by the air pressure.

7. To prevent debris and other foreign objects from entering the engine, plug all openings in the block around the valves being serviced with rags. Now use the special tool to compress the spring of the valve being serviced.

8. Using tweezers or a magnetized rod, remove the valve keepers from the grooves in the valve stem.

9. Remove the spring retainer, the spring shield, and the spring from the valve stem, then remove the valve stem seal from the valve guide.

If the valve cannot be held closed with compressed air, this indicates a leak caused by mechanical damage to the valve face or valve seat. In this case, remove the cylinder head from the engine to perform the necessary repair.
10. Secure a rubber sleeve or wrap tape around the upper end of the valve stem to prevent the valve from falling into the combustion chamber, then shut off the air supply to the cylinder.
11. Inspect the valve stem for signs of wear or mechanical damage. Rotate the valve inside the valve guide and check the radial play at the valve tip to determine the straightness of the stem (replace a bent valve).
12. Move the valve up and down in the valve guide to check for binding. Binding indicates either a bent valve stem or a damaged guide. In either case, remove the cylinder head for the necessary repair.
13. Restore the air supply to the cylinder to hold the valve in place. Remove the rubber sleeve/tape from the valve stem.
14. Lubricate the valve stem with clean engine oil and install a new valve stem seal.

Intake valve stem seals are fitted with a white spring, and exhaust valve stem seals with a black spring.
15. Install the valve spring(s) onto the valve stem (with the closely wound coil end facing the cylinder head).

16. Place the spring retainer on the spring, then compress the spring(s) with the special tool and carefully fit the valve keepers into the groove on the valve stem. To temporarily hold the keepers in place until the tool is released, coat them on the inside with heavy grease.

17. Check that the keepers are seated correctly in the groove, then release the spring compressor.
18. Shut off the air supply to the cylinder and unscrew the adapter from the spark plug hole.
19. Install the rocker arm assembly (see Rocker Arm Assembly Removal, Inspection and Installation).
20. Install the cylinder head cover (see Cylinder Head Cover Removal and Installation).
21. Install the spark plugs and connect the spark plug wires (in the required order).
22. Start the engine and check for oil leaks and abnormal noises from the valve train.