Cylinder Head Assembly: Service and Repair
This article has been updated with bulletin No.: 77-61-14CYLINDER HEAD REPLACEMENT
Cylinder head bolt tightening sequence:
REMOVAL
1. Disconnect battery ground cable.
2. Remove intake manifold.
3. Label, then remove injection lines.
4. Remove rocker arm covers.
5. Drain cooling system, then raise and support vehicle.
6. Disconnect exhaust pipe from manifold.
7. Lower vehicle. Remove A/C compressor from right side cylinder head, then disconnect ground strap.
8. Remove following components from the left/right cylinder heads:
a. Remove power steering pump and position aside.
b. Remove alternator and rear bracket and position aside.
c. Remove A/C compressor and bracket.
d. Remove upper radiator hose, wiring harness/clips and position aside.
e. Remove glow plug relay and dipstick tube.
9. Disconnect coolant sensor electrical connector from cylinder head.
10. Disconnect and remove glow plug wires using tool No. J-39083, or equivalent, as the connectors cannot be reached by hand. Do not pull on glow plug wire harness.
11. Remove rocker arm assemblies and pushrods. Place components on a workbench in order removed for installation in cylinders from which they were removed.
12. Disconnect radiator, bypass and heater hoses.
13. Remove ground straps.
14. Remove water crossover pipe and thermostat housing assembly.
15. Remove cylinder head attaching bolts. The rear bolt in the left side cylinder head may have to remain in the head during removal.
16. Remove cylinder head.
INSTALLATION
IMPORTANT:
- The cylinder head torquing sequence has been revised. The new procedure incorporates torque angle in the final tightening sequence, similar to the current crankshaft and bearings installation procedure. For all model years of the 6.5L engine, use the information provided in this bulletin.
- Make sure that the block gasket surfaces are clean.
- The head gasket material is soft. Handle the gasket with care. Make sure the gasket surface is not creased or dented.
- Do not use a sealer on the Head Gasket. The head gasket is made with sealant on the gasket surface. Additional sealer may cause leakage or malfunction. In addition, some sealers may attack the initial sealant on the gasket.
1. Install the cylinder head gaskets to the block, over the cylinder head dowel pins.
Cylinder Head Bolt Tightening Sequence:
2. Install the cylinder heads to the block, over the cylinder head gaskets and the cylinder head dowel pins.
3. Apply thread sealant GM P/N 12345382 or equivalent, to the bolt threads and under the bolt heads.
FASTENER 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.
4. Install the cylinder head bolts using the installation and tightening sequence shown.
TIGHTEN
- In sequence (Figure 2), tighten all of the cylinder head bolts to 25 Nm (20 lb ft).
- In sequence (Figure 2), tighten all of the cylinder head bolts to 75 Nm (55 lb ft.
- In sequence (Figure 2), retighten all of the cylinder head bolts to 75 Nm (55 lb ft).
- In sequence (Figure 2), tighten all of the cylinder head bolts and additional 90 degrees - 100 degrees (1/4 plus turn).
5. Reverse removal procedure.