Cylinder Head Assembly: Service and Repair
REMOVAL1. Perform fuel system pressure release procedure before attempting any repairs.
2. Disconnect negative battery cable.
3. Drain cooling system.
4. Remove throttle body air inlet hose and air cleaner housing assembly.
5. Remove intake manifold.
6. Disconnect heater hose from thermostat housing.
7. Remove heater tube support bracket from cylinder head.
8. Disconnect camshaft position sensor electrical connector.
9. Disconnect EGR solenoid electrical connector.
10. Raise vehicle on hoist.
11. Disconnect exhaust pipe from exhaust manifold.
12. Remove accessory drive belts.
13. Remove crankshaft damper.
14. Remove upper and lower timing belt covers.
15. Remove timing belt.
16. Remove camshaft sprockets.
17. Remove timing belt idler pulley and rear timing belt cover.
18. Remove cylinder head cover.
19. Remove camshafts and rocker arms.
20. Remove cylinder head bolts and remove cylinder head from engine block.
21. Inspect and clean cylinder head.
CLEANING
To ensure engine gasket sealing, proper surface preparation must be performed, especially with the use of aluminum engine components and multi-layer steel cylinder head gaskets.
NOTE: Multi-Layer Steel (MLS) head gaskets require a scratch free sealing surface.
Remove all gasket material from cylinder head and block. (Refer to 9 - ENGINE - STANDARD PROCEDURE) Be careful not to gouge or scratch the aluminum head sealing surface.
Clean all engine oil passages.
INSPECTION
1. Cylinder head must be flat within 0.1 mm (0.004 inch) (Fig. 9).
2. Inspect camshaft bearing journals for scoring.
3. Remove carbon and varnish deposits from inside of valve guides with a reliable guide cleaner.
4. Using a small hole gauge and a micrometer, measure valve guides in 3 places top, middle and bottom (Fig. 10). Replace guides if they are not within specification.
5. Check valve guide height (Fig. 11).
INSTALLATION
NOTE: The Cylinder head bolts should be examined BEFORE reuse. If the threads are necked down, the bolts must be replaced (Fig. 12).
Necking can be checked by holding a scale or straight edge against the threads. If all the threads do not contact the scale, the bolt should be replaced.
1. Before installing the bolts, the threads should be coated with engine oil.
2. Position cylinder head gasket on block.
3. Install cylinder head on block.
4. Tighten the cylinder head bolts in the sequence shown in (Fig. 13). Using the 4 step torque turn method, tighten according to the following values:
- First: All to 34 Nm (25 ft. lbs.)
- Second: All to 68 Nm (50 ft. lbs.)
- Third: All to 68 Nm (50 ft. lbs.)
CAUTION: Do not use a torque wrench for the following step.
- Fourth: Turn an additional 1/4 Turn
5. Install rocker arms and camshafts.
6. Install cylinder head cover.
7. Install rear timing belt cover and timing belt idler pulley.
8. Install camshaft sprockets.
9. Install timing belt.
10. Install upper and lower timing belt covers.
11. Install crankshaft damper.
12. Install accessory drive belts.
13. Connect exhaust pipe to exhaust manifold. Torque fasteners to 28 Nm (250 in. lbs.).
14. Connect camshaft position sensor electrical connector.
15. Connect EGR solenoid electrical connector.
16. Install heater tube support bracket to cylinder head.
17. Connect heater hose to thermostat housing.
18. Install intake manifold.
19. Install throttle body air inlet hose and air cleaner housing assembly.
20. Fill cooling system.
21. Connect negative battery cable.