1. Disconnect both the battery negative cables from the batteries. Refer to Battery Replacement in Engine Electrical.



2. Disconnect the engine wiring harness at the gray connecting at the rear of the engine.
3. Drain the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.
4. Remove the engine cooling fan from the water pump. Refer to Fan Clutch Replacement in Engine Cooling.
5. Remove the lower intake manifold from the cylinder heads. Refer to Intake Manifold Replacement .

Important: When performing the following service procedure, it is not necessary to completely remove the A/C compressor from the vehicle.

6. Remove the air conditioning compressor from the left accessory bracket and position to the side and secure.
7. Remove the left accessory bracket from the cylinder head (if servicing the left cylinder head). Refer to Accessory Brackets Replacement .
8. Remove the right accessory bracket from the cylinder head (if servicing the right cylinder head). Refer to Accessory Brackets Replacement .
9. Remove the fuel filter/water separator from the lower intake manifold and secure to the side.
10. Remove the left exhaust manifold from the cylinder head (if servicing the left cylinder head). Refer to Exhaust Manifold Replacement .
11. Remove the right exhaust manifold from the cylinder heads (if servicing the right cylinder head). Refer to Exhaust Manifold Replacement .



12. Remove the ground strap from the right rear cylinder head.



13. Remove the front lower cylinder head bolt (5) and drain the coolant from the engine block.

13.1.

Insert a copper tube 1/4 in x 12 to 18 in long into the cylinder head bolt hole with a hose attached.

13.2.

Siphon the coolant from the cylinder head.

14. Remove the valve rocker arm, shaft, and push rod from the cylinder head. Refer to Valve Rocker Arm, Shaft, and Push Rod Replacement .
15. Remove the siphon hose from the engine block.

Important: Use a rubber band to secure the left rear cylinder head bolt into position before removing the cylinder head.

16. Remove the cylinder head bolts in sequence from the engine block.



17. Remove the cylinder head from the engine block.



18. Remove the cylinder head gasket from the engine block.
19. Disassemble the cylinder head. Refer to Cylinder Head Disassemble .
20. Inspect the sealing surfaces of the engine block.
21. Clean the threads on the cylinder head bolts.

Important: The cylinder head gasket material is soft. Handle the cylinder head gasket with care and make sure that the sealing surfaces are not damaged. The engine block surfaces must be clean. Do not use a sealer on the cylinder head gaskets. The cylinder head gaskets are manufactured with the proper amount of sealant "Printed" on its surface. Additional sealer may cause leakage or a malfunction. In addition, some sealers may attack the sealant already on the cylinder head gasket.

1. Assemble the cylinder head. Refer to Cylinder Head Assemble .
2. Install the cylinder head gaskets to the engine block.
3. Apply thread sealant to the cylinder head bolts before installing.




Important: Use a rubber band to hold the right rear cylinder head bolts in place while installing the right cylinder head.

4. Install the cylinder head to the engine block.



5. Apply sealant GM P/N 12346004 or equivalent to the bolt threads and under the bolt heads.

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.

6. Install the remaining cylinder head bolts in the cylinder head.

Tighten

1. Tighten the bolts to 25 N·m (20 lb ft).
2. Tighten the bolts to 75 N·m (55 lb ft).
3. Retighten the bolts to 75 N·m (55 lb ft).
4. In sequence, tighten all the bolts an additional 90 to 100 degrees (1/4 + turn).
7. Install the valve rocker arm, shaft, and push rods on the cylinder head. Refer to Valve Rocker Arm, Shaft, and Push Rod Replacement .



8. Install the ground strap to the right rear cylinder head.
9. Install the left accessory bracket to the cylinder head (if servicing the left cylinder head). Refer to Accessory Brackets Replacement .
10. Install the right accessory bracket to the cylinder head (if servicing the right cylinder head). Refer to Accessory Brackets Replacement .
11. Install the engine cooling fan to the water pump pulley. Refer to Fan Clutch Replacement in Engine Cooling.
12. Install the lower intake manifold to the cylinder heads. Refer to Intake Manifold Replacement .
13. Install the right exhaust manifold to the cylinder head (if the right cylinder head is being serviced). Refer to Exhaust Manifold Replacement .
14. Install the left exhaust manifold to the cylinder head (if the left cylinder head is being serviced). Refer to Exhaust Manifold Replacement .
15. Install the engine wiring harness if necessary.



16. Install the fuel filter/water separator to the lower intake manifold.



17. Connect the engine wiring harness at the gray connector at the rear of the engine.
18. Install the engine cover to the upper intake manifold.
19. Refill the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.
20. Connect both the battery negative cables to the batteries. Refer to Battery Replacement in Engine Electrical.