Cylinder Head Assembly: Service and Repair

Cylinder Head Replacement

Removal Procedure

1. Disconnect the battery negative cable from the battery. Refer to Battery Cable Replacement (Negative Cable to Engine) Battery Cable Replacement (Negative Cable to Engine)Battery Cable Replacement (Positive Cable) Service and RepairBattery Cable Replacement (Negative Cable to Frame) Battery Cable Replacement (Negative Cable to Frame) in Engine Electrical.




2. Drain the cooling system. Refer to Cooling System Draining and Filling Cooling System Draining and Filling in Engine Cooling.
3. Remove the engine electrical wiring harness and lay to the side.
4. Disconnect the engine ground straps. Refer to Engine Ground Strap Replacement Service and Repair in Engine Electrical.
5. Remove the generator from the mounting bracket. Refer to Generator Replacement (L21/LP4) Generator Replacement (L21/LP4)Generator Replacement (LG5) Generator Replacement (LG5) in Engine Electrical.
6. Remove the generator mounting bracket from the engine block. Refer to Accessory Mounting Brackets Replacement (With AC) Accessory Mounting Brackets Replacement (With AC)Accessory Mounting Brackets Replacement (Generator) Accessory Mounting Brackets Replacement (Generator) in Engine Electrical.
7. Remove the upper intake manifold from the lower intake manifold. Refer to Intake Manifold Replacement (Upper Intake Manifold) Intake Manifold Replacement (Upper Intake Manifold)Intake Manifold Replacement (Lower Intake Manifold) Intake Manifold Replacement (Lower Intake Manifold).
8. Remove the lower intake manifold from the engine block. Refer to Intake Manifold Replacement (Upper Intake Manifold) Intake Manifold Replacement (Upper Intake Manifold)Intake Manifold Replacement (Lower Intake Manifold) Intake Manifold Replacement (Lower Intake Manifold)
9. Remove the valve rocker arm covers from the cylinder head. Refer to Valve Rocker Arm Cover Replacement Service and Repair.
10. Remove the valve rocker arm from the cylinder head. Refer to Valve Rocker Arm and Push Rod Replacement Service and Repair.
11. Remove the pushrod from the engine block. Refer to Valve Rocker Arm and Push Rod Replacement Service and Repair.
12. Remove the spark plugs from the cylinder heads. Refer to Spark Plug Replacement Service and Repair in Engine Electrical.




13. Remove the exhaust manifolds from the cylinder head. Refer to Exhaust Manifold Replacement Service and Repair.




14. Remove cylinder head bolts from the engine block.
15. Remove the cylinder heads and gasket from the engine block.
16. Clean and inspect the sealing surfaces on the cylinder heads. Refer to Cylinder Head Cleaning and Inspection 45. Cylinder Head Cleaning and Inspection.

Installation Procedure

Important: Do not use sealer on the composition gaskets, and make sure that the punch code (7.4L) on the cylinder head gasket is facing up.








1. Install the cylinder head gasket to the engine block.
2. Install the cylinder head to the engine block.
Important: Make sure that the threads on the cylinder head bolts are clean as well as the threaded holes in the engine block.


3. Coat the threads of the cylinder head bolts with sealing compound GM P/N 12346004.
4. Install the cylinder head bolts to the cylinder head. Refer to Cylinder Head Installation (Left) 76. Cylinder Head Installation - LeftCylinder Head Installation (Right) 75. Cylinder Head Installation - Right and Cylinder Head Installation (Left) 76. Cylinder Head Installation - LeftCylinder Head Installation (Right) 75. Cylinder Head Installation - Right.
5. Install the push rod into the engine block. Refer to Valve Rocker Arm and Push Rod Replacement Service and Repair.
6. Install the valve rocker arm to the cylinder head. Refer to Valve Rocker Arm and Push Rod Replacement Service and Repair.
7. Install the valve rocker arm covers to the cylinder head. Refer to Valve Rocker Arm Cover Replacement Service and Repair.




8. Install the exhaust manifolds to the cylinder heads. Refer to Exhaust Manifold Replacement Service and Repair.
9. Install the spark plugs to the cylinder head. Refer to Spark Plug Replacement Service and Repair in Engine Electrical.
10. Install the lower intake manifold to the cylinder head. Refer to Intake Manifold Replacement (Upper Intake Manifold) Intake Manifold Replacement (Upper Intake Manifold)Intake Manifold Replacement (Lower Intake Manifold) Intake Manifold Replacement (Lower Intake Manifold).
11. Install the upper intake manifold to the lower intake manifold. Refer to Intake Manifold Replacement (Upper Intake Manifold) Intake Manifold Replacement (Upper Intake Manifold)Intake Manifold Replacement (Lower Intake Manifold) Intake Manifold Replacement (Lower Intake Manifold).
12. Install the engine ground straps to the engine block. Refer to Engine Ground Strap Replacement Service and Repair in Engine Electrical.
13. Install the generator mounting bracket to the engine block. Refer to Accessory Mounting Brackets Replacement (With AC) Accessory Mounting Brackets Replacement (With AC)Accessory Mounting Brackets Replacement (Generator) Accessory Mounting Brackets Replacement (Generator) in Engine Electrical.
14. Install the generator to the mounting bracket. Refer to Generator Replacement (L21/LP4) Generator Replacement (L21/LP4)Generator Replacement (LG5) Generator Replacement (LG5) in Engine Electrical.
15. Install the engine electrical wiring harness.
16. Fill the cooling system. Refer to Cooling System Draining and Filling Cooling System Draining and Filling in Engine Cooling.
17. Connect the battery negative cable to the battery. Refer to Battery Cable Replacement (Negative Cable to Engine) Battery Cable Replacement (Negative Cable to Engine)Battery Cable Replacement (Positive Cable) Service and RepairBattery Cable Replacement (Negative Cable to Frame) Battery Cable Replacement (Negative Cable to Frame) in Engine Electrical.