Cylinder Head Assembly: Service and Repair

1. Disconnect the battery ground cable, then remove intake and exhaust manifolds.
2. Drain cooling system, then disconnect the upper radiator hose at engine.
3. Remove fan and shroud.
4. Remove sleeve nuts, then disconnect injection pipes.
5. Remove nozzle holder fixing nuts, then nozzle holder assembly.

Fig. 34 Rocker arm bracket bolt loosening sequence.:

Fig. 35 Rocker arm shaft bolts removal sequence.:

6. Remove cam cover.
7. Using sequence shown in Fig. 34 and 35, remove rocker arm shaft bracket bolts and nuts, then remove rocker arm shaft and rocker arm assembly.
8. Remove pushrods.
9. Remove joint bolt, then disconnect leak-off pipe.

Fig. 5 Cylinder head bolt removal sequence:

10. Remove cylinder head attaching bolts in sequence shown in Fig. 5, then the cylinder head.
11. Clean all gasket surfaces thoroughly. Install a new head gasket, then the head and head bolts.

Fig. 6 Cylinder head bolt torque sequence:

12. Torque bolts to an initial torque of 40-47 ft. lbs. (5.5-6.5 kg-m) in sequence shown in Fig. 6. Then torque bolts to a final torque of 54-61 ft. lbs. (7.5-8.5 kg-m) if new bolts are used, or 61-69 ft. lbs. (8.5-9.5 kg-m) if the original bolts are used.
13. Reconnect the leak-off pipe and install the joint bolt.
14. Install the push rods.
15. Prior to installation, apply a generous amount of engine oil to the rocker arm shaft, rocker arms and valve stem end caps.

Fig. 36 Rocker arm bracket bolt tightening sequence.:

Fig. 37 Rocker arm shaft bolts installation sequence.:

16. Install rocker arm shaft assembly and tighten bolts in sequence as shown in Fig. 36 and 37.

Fig. 7 TDC timing mark:

17. Bring No. 1 piston to top dead center compression stroke by turning crankshaft until timing mark on pulley aligns with pointer, Fig. 7
18. Adjust the intake valve of Nos. 1 and 2 cylinders and exhaust valve of Nos. 1 and 3 cylinders to specifications.
19. Rotate engine one complete revolution to bring No. 4 piston to top dead center compression stroke.
20. Adjust the intake valve of Nos. 3 and 4 cylinders and exhaust valve of Nos. 2 and 4 cylinders to specifications.
21. Install the cam cover.
22. Install nozzle holder assembly, then nozzle holder fixing nuts.
23. Reconnect injection pipes, then install sleeve nuts.
24. Install fan and shroud.
25. Reconnect the upper radiator hose and refill the engine with coolant.
26. Install intake and exhaust manifolds.
27. Run the engine and check for leaks.