Cylinder Head Assembly: Service and Repair
NOTE: On models with coded audio anti-theft systems, refer to Technician Safety Information for code procedures. On models with air bag system, disarm airbag system as outlined under Technician Safety Information.1. Drain engine coolant into suitable container.
2. Remove camshaft timing pulleys as outlined under Timing Belt.
3. Disconnect accelerator, throttle and cruise cables from throttle body.
4. Remove spark plug wire clamps.
5. Remove lower spark plug wire cover, then the ignition coil.
6. Remove water inlet and inlet housing assembly, then the timing belt rear plates, Fig. 9.
Fig. 9 Cylinder Head Replacement:
7. Remove EGR pipe, then the fuel pressure VSV, Fig. 10.
Fig. 10 Fuel Pressure VSV Replacement:
8. Remove EGR VSV, then EGR valve and modulator.
9. On California models, remove EGR valve adapter.
10. Remove vacuum pipe, Figs. 11 and 12.
Fig. 22 Vacuum Pipe Replacement:
Fig. 12 Vacuum Pipe Replacement:
11. Remove IS valve, then the throttle body.
12. Remove accelerator bracket, then the brake booster union.
13. Remove air intake chamber as follows:
a. Disconnect cold start injector.
b. Remove union bolt and gaskets, then disconnect cold start injector from right delivery pipe.
c. Remove bolts and nuts to intake chamber, then remove intake chamber.
d. Remove cold start injector, tube, wire assembly and gasket.
14. Disconnect engine wire from intake manifold.
15. Disconnect engine wire from wire bracket on right cylinder head.
16. Disconnect heater hoses.
17. Remove delivery pipes and injectors as follows:
a. Disconnect water temperature sensor, cold start injector time switch and water temperature sender gauge connectors.
b. Disconnect connectors from wire bracket on front side of left delivery pipe.
c. Remove six engine wire bolts, then the engine wire.
d. Disconnect injectors.
e. Disconnect fuel hose from fuel tube, then from fuel return pipe.
f. Remove fuel return pipe.
g. Remove four nuts, wire bracket, two delivery pipes, eight injectors, four spacers and eight insulators. Do not drop injectors.
18. Remove intake manifold bolts, then the intake manifold.
19. Remove front water bypass joint, then the rear water bypass joint.
20. Remove front exhaust pipe, then the main catalytic converters.
21. Remove right exhaust manifold.
22. Remove oil dipstick and guide.
23. Remove left exhaust manifold.
24. Remove engine hangers.
25. Remove engine wire brackets from right head.
26. Remove cylinder head covers, Fig. 13.
Fig. 13 Exploded View Of Cylinder Heads:
27. Remove semi-circular plugs if necessary.
28. Remove camshafts as follows:
a. Bring service bolt hole of right exhaust camshaft upward by turning exhaust cam with wrench. Secure cams by placing service bolt through sub-gear and driven gear, Fig. 14.
Fig. 14 Righthand Drive Gear To Sub-gear Alignment:
b. Set timing mark of exhaust camshaft driven gear at 10° angle by turning cam with wrench, Fig. 15.
Fig. 15 Righthand Exhaust Cam Alignment:
c. Remove two bearing cap bolts holding oil feed pipe, then loosen and remove bearing cap bolts in sequence in Fig. 16. After bolts are removed, remove oil feed pipe, bearing caps and camshaft.
Fig. 16 Righthand Exhaust Cam Loosening Sequence:
d. Set timing mark of right intake camshaft at 45° by turning cam with wrench, Fig. 17.
Fig. 17 Righthand Intake Cam Alignment:
e. Remove bearing cap bolts in sequence in Fig. 18. When all bolts are removed, remove bearing caps, oil seal and intake cam.
Fig. 18 Righthand Intake Cam Loosening Sequence:
f. Remove two bearing cap bolts holding oil feed pipe. Then loosen and remove bearing cap bolts in sequence in Fig. 19. After bolts are removed, remove oil feed pipe, bearing caps and camshaft.
Fig. 19 Lefthand Exhaust Cam Loosening Sequence:
g. Bring service bolt hole of left exhaust camshaft upward by turning exhaust cam with wrench. Secure cams by placing service bolt through sub-gear and driven gear, Fig. 20.
Fig. 20 Lefthand Drive Gear To Sub-gear Alignment:
h. Set timing mark of exhaust camshaft driven gear at 15° angle by turning cam with wrench, Fig. 21.
Fig. 21 Lefthand Exhaust Cam Alignment:
i. Set timing mark of left intake camshaft at 60° by turning cam with wrench, Fig. 22.
Fig. 22 Lefthand Intake Cam Alignment:
j. Remove bearing cap bolts in sequence in Fig. 23. When all bolts are removed, remove bearing caps, oil seal and intake cam.
Fig. 23 Lefthand Intake Cam Loosening Sequence:
29. Disconnect ground straps at rear of heads. Remove all cylinder head bolts in sequence shown in, Fig. 24, then remove cylinder heads.
Fig. 24 Cylinder Head Bolt Loosening Sequence:
30. Reverse procedure to install, noting the following:
a. Torque cylinder head bolts to 29 ft. lb., then an additional 90°, in sequence shown in Fig. 25.
Fig. 25 Cylinder Head Bolt Tightening Sequence:
b. Install new circular plugs to heads. Apply seal packing to bearing caps, Fig. 26.
Fig. 26 Bearing Cap Seal Packing Application:
c. Once an intake and exhaust cam is installed, ensure to line up timing marks on the cams, Figs. 27 and 28.
Fig. 27 Righthand Camshaft Timing Mark Alignment:
Fig. 28 Lefthand Camshaft Timing Mark Alignment:
d. Tighten camshaft bearing bolts in the sequence, Figs. 29 and 30.
Fig. 29 Righthand Cam Tightening Sequence:
Fig. 30 Lefthand Cam Tightening Sequence:
e. Check and adjust valve clearance. Refer to Valve, Intake/Exhaust in this section.
31. On models with air bag system, rearm airbag system as outlined under Technician Safety Information. If audio system was disabled, activate as outlined under Technician Safety Information.