1. Disconnect both the battery negative cables from the batteries. Refer to Battery Cable in Engine Electrical.
2. Remove the CDR valve from the valve rocker arm cover.
3. Remove the upper intake manifold from the lower intake manifold . Refer to Intake Manifold Replacement .
4. Remove the lower intake manifold from the cylinder head (s). Refer to Intake Manifold Replacement .
5. Remove the heat shield between the turbocharger and the valve rocker arm cover (right side only).



6. Remove the engine wiring harness from the rear of the right valve rocker arm cover and move to the side (for removing the right side valve rocker arm cover only).




Important: It is not necessary to disconnect the glow plug electrical connector to perform this service procedure.

7. Remove the engine wiring harness from the left side of the engine and move to the side (for removing the left valve rocker arm cover only).

Important: Mark the fuel injection line retaining clips and brackets in order to ensure proper reinstallation.

8. Remove the upper intake manifold from the lower intake manifold. Refer to Intake Manifold Replacement .



9. Remove the braces from the turbocharger. Refer to Turbocharger Replacement .
10. Remove the lower intake manifold from the cylinder head. Refer to Intake Manifold Replacement .

Important: The turbocharger heat shield must be removed from the turbocharger to ensure that the fuel injectors are not damaged during the removal process.

11. Remove the fuel injection lines from the fuel injectors and the fuel injection pump. Refer to Injection Line(s) Replacement in Engine Controls-6.5L.
12. Remove the oil level indicator and tube from the engine block. Refer to Oil Level Indicator and Tube Replacement .



13. Remove the heater hose from heater core inlet. Refer to Heater Hoses Replacement in HVAC.



14. Remove the rear heater hose from the connector (if the vehicle is equipped with rear heat). Refer to Heater Hoses Replacement - Auxiliary in HVAC.



15. Remove the valve rocker arm cover bolts from the cylinder head.




Notice: Prying on the valve rocker arm cover may cause damage to the sealing surfaces. Use a block of wood against the side of the valve rocker arm cover and strike with a hammer in a sideways direction to shear the RTV sealant.

16. Remove the valve rocker arm cover from the cylinder head.
17. Remove the RTV from the valve rocker arm cover.
18. Remove all oil and grease from the sealing surfaces.

Notice: Do not allow the RTV sealant to enter any blind threaded hole. RTV sealant that is allowed to enter a blind threaded hole can cause hydraulic lock of the fastener when the fastener is tightened. Hydraulic lock of a fastener can lead to damage to the fastener and/or the components. Hydraulic lock of a fastener can also prevent the proper clamping loads to be obtained when the fastener is tightened. Improper clamping loads can prevent proper sealing of the components allowing leakage to occur. Preventing proper fastener tightening can allow the components to loosen or separate leading to extensive engine damage.

1. Apply a 5 mm (3/16 inch) bead of RTV sealant GM P/N 12345739 to the valve rocker arm cover, inboard of the bolt holes. The sealer must be wet to the touch when the bolts are tighten.



2. Install the valve rocker arm cover to the cylinder head.




Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

3. Install the valve rocker arm cover bolts to the cylinder head.

Tighten
Tighten the bolts to 22 N·m (16 lb ft).




4. Install the fuel injection lines to the fuel injection pump and fuel injectors. Refer to Injection Line(s) Replacement in Engine Controls-6.5L.
5. Install the lower intake manifold on the cylinder heads. Refer to Intake Manifold Replacement .



6. Install the heater hose to heater core inlet. Refer to Heater Hoses Replacement in HVAC.



7. Install the rear heater hose to the connector if the vehicle is equipped with rear heat. Refer to Heater Hoses Replacement - Auxiliary in HVAC.



8. Install the engine wiring harness to the right rear or the lower intake manifold (if installing the right side valve rocker arm cover only).
9. Install the engine wiring harness to the left of the lower intake manifold (if installing the left side valve rocker arm cover only).



10. Install the CDR valve to the valve rocker arm cover.
11. Install the heat shield to the turbocharger. Refer to Turbocharger Replacement .
12. Install the upper intake manifold to the lower intake manifold (L 56 shown). Refer to Intake Manifold Replacement .
13. Install the oil level indicator and tube. Refer to Oil Level Indicator and Tube Replacement .



14. Install the braces to the turbocharger. Refer to Turbocharger Replacement .
15. Connect both the battery negative cables to the batteries. Refer to Battery Cable in Engine Electrical.