Tools Required

1. Remove the valve rocker arms. Refer to Valve Rocker Arm and Push Rod Replacement .
2. Remove the spark plug wire from the spark plug for the cylinder to be serviced.

•	Twist the plug wire 1/2 turn.

•	Pull only on the boot in order to remove the wire from the spark plug.





Important: Remove the spark plugs from the cylinder head with the engine at room temperature.

3. Loosen the spark plug 1 or 2 turns.
4. Brush or use compressed air to remove any dirt or debris around the spark plug.
5. Remove the spark plug.



6. Install the J 22794 into the spark plug hole.
7. Attach an air hose to J 22794 .
8. Tap the end of the valve stem with a plastic face hammer in order to loosen any varnish on the valve stem keys.



9. Use the J 38606 in order to compress the valve spring.



10. Remove the valve stem keys  (3).
11. Carefully release the valve spring tension.
12. Remove the J 38606 .
13. Remove the valve spring cap  (4).
14. Remove the valve spring (5).

Important: A second design valve stem oil seal and shim may be used on later engines.

A separate spring shim is not required with the second design seal and shim.
15. Remove the valve stem oil seal (6) (first design).
16. Remove the valve spring shim (7) (first design).
17. Remove the valve stem oil seal and shim (2) (second design).

Important: The LS6 engine uses a copper plated spring shim. A shim of the same design must be installed during assembly.

1. Clean the cylinder head valve spring seat and/or shim area.
2. Install the valve spring shim (7) (first design).
3. Install the valve stem oil seal and shim (2) (second design).

The J 42078 is not required for installation of the second design seal and shim.





Important: The valve stem oil seal alignment and position on the valve guide is critical.

An improperly installed valve stem oil seal may lead to excessive oil consumption, and increased vehicle emissions .
4. Install the valve stem oil seal (first design) onto the guide.

4.1.	Lubricate the valve guide and valve stem oil seal with clean engine oil.

4.2.	Install the valve stem oil seal (first design) onto the valve stem. Push the seal down until the seal contacts the valve guide.

4.3.	Use the J 42078 in order to install the oil seal.

Push or lightly tap the tool until the tool bottoms against the valve spring shim.




5. Measure the valve stem oil seal (first design) for the properly installed height.

There should be a 18.1-19.1 mm (0.712-0.752 in) gap between the top edge of the oil seal body and the valve spring shim surface.




6. Install the valve spring to the J 38606 .
7. Compress the valve spring using the J 38606 .
8. Install the valve spring to the cylinder head.



9. Install the valve spring cap  (4).
10. Install the valve stem keys  (3).

•	Use grease to hold the keys  (3) in place and remove J 38606 .

•	Make sure the keys  (3) seat properly in the groove of the valve stem.

•	Carefully release the valve spring pressure, making sure the valve keys stay in place.

•	Remove the J 38606 .

•	Tap the end to the valve stem with a plastic faced hammer to seat the keys (if necessary).




11. Disconnect and remove the air supply from the J 22794 .
12. Remove the J 22794 from the spark plug hole.



13. Measure the valve spring installed height using a ruler.

Measure from the base of the valve spring to the top of the valve spring.

•	If the installed height exceeds 46.25 mm (1.82 in), install a valve spring shim of approximately 0.5 mm (0.02 in) thick.

•	Do not shim the valve spring to obtain less than the specified height.

•	Do not assemble the components without a spring shim on the cylinder head.

14. Remove the air hose from the J 22794 .

Notice: Refer to Fastener Notice in the Preface section.




15. Instal the spark plug by hand until snug.
16. Tighten the spark plug.

Tighten
Tighten the spark plugs to 15 N·m (11 lb ft).




17. Install the spark plug wire to the spark plug.
18. Install the valve rocker arms. Refer to Valve Rocker Arm and Push Rod Replacement .