If engine oil or coolant leaks are detected at the joints between the cylinder head and the cylinder block, remove the head and replace its gasket.
A leak may also occur as a result of warping of the cylinder head due to overheating.
1. Reduce the pressure in the fuel system (see "Reducing pressure in the fuel system").
2. Disconnect the wire from the negative terminal of the battery.
3. Drain the cooling system (see "Replacing the coolant").
4. Remove the air filter (see "Removal and installation the air filter and air duct").
5. Press the lock and disconnect the wiring harness connector from the exhaust camshaft variable valve timing system valve.
6. Similarly, disconnect the wiring harness connector from the intake camshaft valve.
7. Remove the timing belt from the camshaft pulleys (see "Replacing the timing belt").
8. Press the release button and disconnect the wiring harness connector from the thermostat heating element.
9. Loosen the engine wiring harness bracket mounting nut, remove the bracket from the stud and move the wiring harness to the side.
10. Disconnect the wiring harness connectors from the exhaust camshaft position sensor A and the intake camshaft position sensor B.
11. Disconnect the wiring harness connectors from the fuel injectors.
12. Unscrew the bolt securing the negative wire tip to the cylinder head and move the tip to the side.
13. Press the lock and disconnect the wiring harness connector from the coolant temperature sensor.
14. Loosen the clamp securing the hose to the thermostat pipe and disconnect the hose from the pipe.
15. Loosen the brake booster vacuum hose clamp by squeezing its bent tabs with pliers. Slide the clamp along the hose and disconnect the hose from the inlet pipe fitting.
16. Squeeze the retainer and disconnect the throttle assembly heating hose tip from the water distributor fitting.
17. Loosen the heater hose clamps by squeezing their bent tabs with pliers. Slide the clamps along the hoses and disconnect the hoses.
18. Remove the catalytic converter (see "Removal and installation the catalytic converter, replacing its gasket").
19. Remove the camshafts (see "Removal, inspection and installation of camshafts").
20. Remove the two bolts securing the water distribution pipe to the water pump...
21. ...bolt for fastening the water distribution pipe to the cylinder block...
22. ...two bolts securing the pipe to the thermostat module...
23. ...and remove the water distribution pipe.
WARNING: The water distribution pipe flanges are sealed with rubber rings. Replace the rings whenever the connections are disassembled.
24. Slide the heat shield along the wire harness, press the wire harness connector lock...
25. ...and disconnect the connector from the oil pressure sensor.
26. Disconnect the plastic holders of the engine wiring harness from the engine brackets by cutting them with pliers, and remove the wiring harness from the engine compartment.
27. Loosen the ten bolts securing the head to the cylinder block in the sequence shown in Figure 5.3 and remove them.
WARNING: The cylinder head bolts may only be removed when the engine is cold.
28. Remove the cylinder head assembly with the intake pipe.
HELPFUL TIP: Remove the cylinder head with an assistant, as it is quite heavy.
29. Remove the cylinder head gasket.
30. Clean the mating surfaces of the cylinder head and block from oxides and remnants of the old gasket.
31. Check the cylinder head for warpage. To do this, place a ruler on the surface of the head, first in the middle along, then across and diagonally, and measure the gap between the surface of the head and the ruler with a feeler gauge. Grind the cylinder head if the gap exceeds 0.1 mm.
32. Install the cylinder head in the reverse order of removal, taking into account the following:
- remove any oil and coolant from the threaded holes of the cylinder head mounting bolts that got there when the head was removed;
- be sure to install a new cylinder head gasket, it cannot be reused;
- lubricate the bolts with engine oil;
- tighten the bolts on a cold engine in the order shown in Figure 5.4, to the torque specified in Appendix 1.
33. Install the camshafts in the sequence specified in subsection "Removal, inspection and installation of camshafts".
34. Install all previously removed parts in the reverse order of removal.
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