Cylinder head — removal and installation (Opel Astra G)

1. Decompress the fuel system (Chapter 4A) and disconnect the battery from ground.

2. Drain the coolant.

3. Remove the camshaft belt.

4. Remove the engine support bracket on the right side of the cylinder head by unscrewing the bolts.

5. Remove both manifolds. The cylinder head can be removed without removing the manifolds by following these steps:.

A. Disconnect the wires and hoses from the throttle body and intake manifold.

B. Loosen the bolts and remove the intake manifold support and upper generator bracket.

B. Disconnect the exhaust pipe from the manifold, disconnect the connector from the oxygen sensor.

6. Remove the cylinder head cover, camshaft sprocket and unscrew the bolts securing the rear cover to the camshaft bearing housing.

7. Mark and disconnect the wires from the cylinder head, disconnect the hose from the thermostat housing.

8. In the reverse order of the indicated (see photo below) gradually loosen the bolts (doing ⅓ of a turn per reception) and remove the camshaft bearing housing (see photo). If necessary, displace the housing with light blows of a soft-faced hammer; do not pry the bearing housing by the split plane. Remove the guide pins if they become loose.



9. Remove the cylinder head. Dislodge the stuck head with light blows of a soft-faced hammer. Remove the guide pins and gasket.

Preparing for assembly

10. Clean the separating surfaces of the head and block, closing all openings to prevent dirt from getting in. Cover the gaps in the pistons with grease, which is then removed.

11. Check for damage on the separating surfaces of the cylinder head and block (deep scratches, chips, etc.). Minor defects are removed with a file, serious damage is removed by grinding the block and head.

12. Check the deformation of the separating surfaces of the head and block.

13. Clean the threads in the cylinder head and tap them with a tap.

14. Replace the cylinder head bolts.

Installation

15. Set the piston of the 1st cylinder to TDC of the compression stroke.

16. Wipe dry the separating surfaces of the head and cylinder block. Make sure the guide pins are present.

17. Place a new gasket on the cylinder block (the OBEN/TOP inscription should be facing up – photo).





18. Check the alignment of the marks on the crankshaft sprocket and the oil pump housing by placing the sprocket in place. Apply to the upper split plane of the head (under the bearing housing) sealant (see photo). Install the cylinder head onto the pins.



18. Install the camshaft bearing housing onto the pins.



19. Carefully insert the bolts into the corresponding holes in the cylinder head (do not drop the bolts), tighten them by hand (see photo).



20. Tighten the cylinder head bolts in the sequence shown (see photo) with the torque of the 1st stage of tightening. Tighten the bolts in the same sequence first to the angle of the 2nd stage, then to the angles of the 3rd and 4th stages.







21. Tighten the bolts securing the rear cover to the camshaft bearing housing.



22. Install the engine support bracket to the right side of the cylinder head. Tighten the bolts.

23. Then assembly is carried out in reverse order.

Original posted on the website: www.opelbook.ru