Removal and Replacement
Cylinder head removal & installation
Model 140:
NOTE: Take off cylinder head together with camshafts, intake manifold and exhaust manifold once engine has cooled down. Seal secondary air injection hole on side right at cylinder heads for engines without secondary air injection hole with end cover part no. 104 016 00 33.
Removing, Installing
1. Drain coolant at crankcase. Disconnect coolant and heating hoses at cylinder head.
2. Position piston of cylinder 1 to ignition TDC.
3. Remove front cover at top. Refer to Timing Components - Timing Cover - Service and Repair - Procedures Service and Repair
4. Mark position of camshaft sprockets to timing chain. To do this, apply colored markings (arrows).
5. Pull off pin, (1) for guide rail or friction rail with impact extractor tool No. 116 589 20 33 00 and threaded bolt tool No. 116 589 01 34 00.
Installation Note: The thread in the pin (1) must be located at the front (in direction of travel) when installed.
Engine 104.98
6. Unbolt guide sprocket (1) (left-hand thread) and take off together with bearing body (2).
7. Unbolt armature at camshaft adjuster.
8. Take timing chain off camshaft sprockets.
9. Unplug position sensor at right wheelhouse.
Installation Note: The connector must be plugged in watertight.
Engine 104.99
10. Take off engine wiring harness. To do this, slacken all the cable ties of the wiring harness and unplug all the connectors.
11. Disconnect cruise control linkage.
Engine 104.99
12. Unplug connector at engine separation point (X26/17).
Unplug connector of electronic accelerator actuator (M16/1x1), press ratchet (arrow), connector turns through 90° by means of a spiral spring.
Remove engine wiring harnesses from cable duct.
13. Detach vacuum pipes at intake manifold (arrow), fit on.
14. Unscrew bolts for exhaust system at flange of exhaust manifold.
15. Detach secondary air injection pipe (1) at the cylinder head. Replace seal.
16. Detach hose at non-return valve of secondary air injection pipe (arrow), unbolt bracket (1).
17. Unbolt bracket of dipstick guide tube and intake manifold support (arrows). On Model 140, remove dipstick guide tube.
18. Detach pipe (43) of crankcase air admission at combination support (17).
19. Briefly open fuel filler cap to release pressure in fuel tank.
Unscrew fuel pipes (arrows).
Counter-hold the connection fitting (1) when slackening the fuel pipe.
20. If Automatic Transmission, unbolt dipstick guide tube at rear of cylinder head (arrow).
21. Detach Bowden cable (30) from the accelerator control lever (9). Compress plastic clip (28) and pull out Bowden cable.
Installation Note: Adjust Bowden cable.
22. Detach control pressure cable (4), compress plastic clip (5) and guide plastic clip with linkage through the bracket.
23. Slacken hose straps at the coolant hose to the coolant pump. Remove heat rig water return pipe.
24. When engine cold, slacken cylinder head bolts in stages in the reverse order of the tightening diagram, beginning with bolt 14.
25. Remove camshaft bearing caps 9 and 13. Install lifting lugs. Lift off cylinder head with engine hoist and liking tackle.
26. Clean contact surface on crankcase and on cylinder head.
27. Replace cylinder head gasket.
NOTE: The cylinder head gasket is not water-tight until the engine has reached operating temperature, in other words, until a swelling operation has taken place. For this reason, the cooling system must not be pressure-tested until after the engine has reached operating temperature.
Installation Note: Pay attention to dowel pins for locating cylinder head on crankcase.
28. Rotate camshafts so that bottom edge of holes in camshaft flange form a level with top edge of the cylinder head and check with 4 mm pins (1).
29. Check TDC position of piston in cylinder 1.
30. Fit on cylinder head with lifting tackle.
31. Examine cylinder head bolts.
32. Oil the thread and the bolt head contact surface of the cylinder head bolts and insert.
NOTE: The length (L) of cylinder head bolts should not exceed 163.5 mm. The cylinder head bolts are subjected to a certain stretch each time they are tightened. If the maximum length (L) is exceeded, the bolts should be replaced.
33. Tighten cylinder head bolts in stages in the order of the tightening diagram beginning with 1.
1st stage, tighten to: 55 Nm
2nd stage, turn an additional 90°
3rd stage, turn an additional 90°
34. Fit on timing chain, pay attention to markings.
35. Remove pins from the camshaft flange.
36. Install in reverse order
Tightening Torques:
Bolts for Cylinder Head Cover: 10 Nm
Bolts of Camshaft Bearing Caps: 21 Nm