Home » 2008 6.6L Duramax » 2008 6.6L Duramax – VALVE STEM OIL SEAL AND VALVE SPRING REPLACEMENT – Removal Procedure


1. Remove the upper and lower fan shroud. Refer to Engine Coolant Fan Lower Shroud Replacement (Mechanical)          and Engine Coolant Fan Upper Shroud Replacement (Mechanical) or Engine Coolant Fan Upper Shroud                        Replacement (Automatic Transmission – Diesel).
2. Remove the valve rocker arm shaft, valve bridges, and pushrods for the cylinder head being serviced. Refer to               Valve Rocker Arm, Shaft, and Push Rod Replacement.

3. Remove the glow plug for the cylinder requiring service.Refer to Glow Plug Replacement – Bank 1 or Glow Plug            Replacement – Bank 2 .
4. In order to apply shop air to the cylinders use the following procedures to modify J 26999- 20 (1) and J 26999             (2):. See Special Tools .
1. Remove the valve core from J 26999-20 to allow air to flow.
2. Remove the quick connect fitting from J 26999 . See Special Tools .
3. Adapt the quick connect fitting in order to use for shop air.
4. Connect the quick connect fitting to J 26999-20 .

IMPORTANT: Rotate the cylinder to be serviced to the bottom of the stroke. This is to ensure that the engine does                                 not rotate when the compressed air is applied to the cylinder being serviced.
5. Install J 26999-20 into the glow plug hole for the cylinder being serviced.
6. Apply compressed air to hold the valves in place. I f the compressed air is released, the valves can drop into the            cylinder.

7. Install J 4 4 6 4 6 to the rocker arm bosses on the cylinder head. See Special Tools.
J 4 4 646 should be installed in the rocker arm boss next to the cylinder being serviced. See Special Tools . The            pivot pin can be removed from the stand to allow the stand to be installed. The lever has different locating holes          for the pivot pin depending on available clearance. The lever is also notched for different locations of the                        compressor.
8 . Using J 4 4 6 4 6 compress the valve spring. See Special Tools .

9. Remove the valve keys (1) from the valve stem
10. Carefully release the valve spring tension.

11. Remove the valve spring upper seat (2) and the valve spring (3).
12. Remove the valve stem oil seal (4).
13. Remove the valve spring lower seat (5).
14. Continue removing the remaining valve stem seals for the cylinder using the above procedure.