Tools Required

J 39083 Glow Plug Connector Tool

1. Remove the intake manifold. Refer to Intake Manifold Replacement .
2. Disconnect the fuel injection lines. Refer to Diesel Fuel Injection.
3. Remove the valve rocker arm covers. Refer to Valve Rocker Arm Cover Replacement .
4. Drain the cooling system.
5. Raise the vehicle.
6. Support the vehicle with safety stands.
7. Remove the exhaust pipe from the exhaust manifold. Refer to Exhaust System.
8. Lower the vehicle.



9. Remove the components as follows for the left cylinder head:

•	The air conditioning compressor and the bracket. Refer to Heating, Ventilation, and Air Conditioning.

•	The power steering pump with the bracket. Refer to Power Steering Gear and Pump.

•	The glow plug relay

•	The oil level indicator tube

•	The upper radiator hose

•	The wiring harness

10. Remove the following components for the right cylinder head:

•	The ground strap

•	The generator and the rear bracket

•	The vacuum pump and the bracket

•	The turbocharger assembly. Refer to Turbocharger.

•	The wire harness at the clips and move aside

11. Disconnect the wire from the coolant sensor at the cylinder head.



12. Remove the glow plug wires. Use the J 39083 in order to disconnect the glow plug connectors from the glow plugs on the right hand cylinder head. The connector cannot be reached with the hand. Do not pull on the glow plug harness wire.

Important: The valve rocker arm assemblies and the pushrods must be marked for proper assembly.

13. Remove the valve rocker arm assemblies and the pushrods. Refer to Valve Rocker Arm and Push Rod Replacement .
14. Remove the water pump bypass and the heater hoses.
15. Remove the coolant crossover pipe/thermostat housing assembly.
16. Remove the exhaust manifold. Refer to Exhaust Manifold Replacement .
17. Remove the cylinder head bolts. The rear bolt in the left cylinder head may have to remain in the head during removal.



18. Remove the cylinder head.
19. Clean the following parts:

•	The carbon deposits from the combustion chambers

•	Clean all traces of the old head gasket from the cylinder head and block. The use of a motorized wire brush is not recommended.

•	The cylinder head bolt threads using a wire brush

•	The metal chips and dirt from the threads in the block

20. Inspect the following components:

•	The cylinder head for cracks between the intake and exhaust ports. Use the magnaflux or dye method if available.

•	The sealing surfaces of the block and cylinder head for nicks, heavy scratches or other damage

•	The block for missing or damaged dowel pins or dowel pins in the wrong location

21. Measure the following items:

•	The cylinder head warpage.

•	The pre-chamber installed depth.

Important: 

•	The block gasket surfaces must be clean.

•	Do not use a sealer on the head gasket. The head gasket is manufactured with the proper amount of sealant "printed" on its surface. Additional sealer may cause leakage or malfunction. In addition, some sealers may attack the sealant already on the head gasket.

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.




1. Install the head gasket to the block over the dowel pins.

Connect the rear cylinder head bolt to the cylinder head (left cylinder head). Due to the clearances, the bolt must be installed at this time.

2. Install the cylinder head. Make sure the gasket surfaces are clean. Guide the head carefully in place over the dowel pins.



3. Install the cylinder head bolts.

•	Check the cylinder head bolts for stretching.

•	Make sure the bolt threads are clean.

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

4. Tighten the cylinder heads in the following 3 passes:

Tighten

•	Tighten the bolts to 25 N·m (20 lb ft).

•	Tighten the bolts to 75 N·m (55 lb ft).

•	In sequence, tighten all the bolts an additional 90-100 degrees (1/4 + turn).

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.

5. Install the exhaust manifold to the cylinder head.

Tighten

1. Tighten the exhaust manifold bolts to 35 N·m (26 lb ft).
2. Tighten the exhaust manifold nuts and mounting studs to 35 N·m (26 lb ft).
6. Install the coolant crossover pipe/thermostat assembly. Use new gaskets.

Tighten
Tighten bolts to 42 N·m (31 lb ft).

7. Install the water pump bypass and heater hoses.
8. Install the pushrods and the valve rocker arm assemblies, in their original locations.



9. Install the glow plug wires. Use the J 39083 in order to connect the glow plug connectors to the glow plugs.
10. Connect the wire to the coolant sensor at the cylinder head.
11. Install the components as follows for the right cylinder head:

•	The turbocharger assembly

•	The ground strap

•	The generator and rear bracket

•	The vacuum pump and bracket

•	The wiring harness at the clips and move aside

12. Install the components as follows for the left cylinder head:

•	The air conditioning compressor and bracket

•	The power steering pump with bracket

•	The glow plug relay

•	The oil level indicator tube

•	The upper radiator hose

•	The wiring harness

13. Raise the vehicle.
14. Support the vehicle with safety stands.
15. Install the exhaust pipe to the exhaust manifold. Refer to Exhaust Systems.
16. Lower the vehicle.
17. Install the valve rocker arm covers.
18. Install the fuel injection lines.
19. Install the intake manifold.
20. Fill the cooling system with the proper quantity and grade of coolant.
21. Change the engine oil and the filter. Refer to Maintenance and Lubrication.