Cylinder head — removal and installation (engine in a car) (Opel Vectra A)

Note: When removing the cylinder head, the engine must be cold. When installing, use new cylinder head bolts, a new cylinder head gasket and a new timing belt. Tightening torques (as shown in Section 2A) apply to the latest bolts only. Earlier bolts are tightened to different torques. Consult your supplier.

Removal

1. Disconnect the negative cable from the battery.

2. Drain the cooling system as described in Section 3.

3. Remove the front part of the exhaust system as described in Section 4C.

4. The cylinder head can be removed together with the intake manifold, or the intake manifold can be separated from the cylinder head before removal as described in Section 4B. If no work is to be done on the intake manifold, it can be unscrewed from the cylinder head and moved to the side, thus eliminating the need to disconnect the corresponding hoses, pipes and electrical wiring.

5. If the cylinder head is to be removed together with the intake manifold, disconnect all associated hoses, pipes and wiring from the manifold and associated components, using the Section 4B; unscrew the mounting bracket from the manifold. Loosen the generator mountings as described in Section 5, then unscrew the upper generator mount from the intake manifold.

6. If the intake manifold needs to be left in the engine compartment, proceed as follows, otherwise go to step 17.

7. Disconnect the electrical wiring from the air flow meter and the breather hose from the heater unit on the throttle body. Disconnect the air cleaner hose and remove the air flow meter/heater unit assembly from the throttle body. See. Section 4B if necessary.



8. Disconnect the end of the cable from the throttle lever, then unscrew the cable bracket and remove it from the intake manifold.

9. Unscrew the two fastening nuts of the ground loop from the fuel line (one at each end), and disconnect the three ground loops.

10. Disconnect the wiring from the throttle position switch.

11. Pull the cover off the wiring harness, disconnect the wiring from the fuel injectors by squeezing the fastening brackets. Move the wiring harness cover to the side.

12. Disconnect the two breather hoses at the rear of the camshaft cover.

13. Loosen the generator fasteners as described in Section 5, then remove the upper generator fastener from the intake manifold.

14. Unscrew the bracket from the manifold.

15. Make a final check to ensure that there are no hoses, pipes or wires left unconnected, then remove the mounting nuts and lift the intake manifold off the cylinder head. Make sure that the manifold is securely fastened, being careful not to deform any hoses, pipes, wires etc. that are still connected.

16. Remove the manifold gasket from the cylinder head

17. Remove the timing belt, camshaft sprockets, tensioner and idler pulleys as described in Chapter 4.

18. Remove the upper and middle posts for the outer drive belt cover mounting screws. Note that the upper post simply unscrews from the cylinder head, while the middle post is attached with a bolt.

19. Remove the two upper bolts securing the rear timing belt cover to the cylinder head

20. Remove the distributor cover and high-tension wires as described in Section 5.



21. Disconnect the distributor wiring.

22. Disconnect the coolant hose at the left end of the cylinder head

23. Remove the bolt securing the crankcase breather pipe bracket to the end of the cylinder head.

24. Disconnect the upper radiator hose from the thermostat housing, disconnect the electrical wiring from the temperature gauge sensor and the coolant temperature sensor (both are located in the thermostat housing).

25. Make a final check to ensure all relevant hoses, pipes and wires are disconnected.

26. On the X20 XEV model, remove the camshaft as described in Chapter 7.

27. With the end socket in the order shown (see illustrations), loosen all cylinder head bolts by a quarter turn, then loosen all bolts by a half turn, and finally completely loosen and remove the bolts. Remove the washers. Note that the sequence for loosening the bolts on the X20 XEV engines and the DOHC engines is different.





28. Lift the head off the cylinder block. If necessary, gently tap the head with a mallet to free it. Note that the cylinder head rests on pins.



29. Remove and discard the cylinder head gasket.

30. Clean the mating surfaces of the head and cylinder block. Do not damage the working surface of the head. Cover the cooling channels and other openings with adhesive tape or cloth to prevent dirt and carbon from entering. Remove all oil from the bolt holes, if oil accidentally remains in the holes, when tightening the bolts, the hydraulic pressure can crack the block.

31. If required, the cylinder head can be disassembled and inspected as described in Chapter 10.

Installation

32. Installation begins by positioning the new gasket on the block so that the word "OBEN" or "TOP" is facing up and is located at the end of the engine with the timing belt.

33. After thoroughly cleaning the mating surfaces, position the head on the block so that the pins enter the corresponding holes,

34. Temporarily install the crankshaft pulley and camshaft sprockets, before removing the toothed drive belt, check that the timing marks remain in place (see Chapter 4).

35. Install new cylinder head mounting bolts together with washers, screw them in by hand as far as possible.

36. Tighten the bolts in the order shown (see illustrations). Please note that the tightening sequence on the X20 XEV engines is different than other DOHC engines. Tighten the bolts in the four stages given in Specifications (see section 2A, for 2.0 liter) - that is, tighten all bolts to Stage 1 torque, then tighten all bolts to Stage 2 torque, and so on (see illustrations).









37. Further installation is carried out in a figurative order, paying attention to the following.



38. Install the timing belt tensioner and idler pulleys, camshaft sprockets and new timing belt as described in Chapter 4. Tension the toothed drive belt as described in Chapters 4 and 5.

39. Where necessary, install the intake manifold to the cylinder head as described in Section 4B, using a new gasket.

40. Install the front part of the exhaust system as described in Section 4C, using a new gasket.

41. Install the upper generator mount to the intake manifold (where it is applied), then adjust the tension of the alternator drive belt as described in Section 5.

42. Fill the cooling system (Section 3).

43. Finally, make sure that all relevant hoses, pipes, wires, etc., have been reconnected.

44. After starting the engine, check for leaks.

45 Once the engine has warmed up to normal operating temperature, check and, if necessary, adjust the mixture quality (if possible), as described in Section 4B.