Cylinder Head Assembly: Service and Repair

NOTE: Remove cylinder head together with camshaft, intake manifold and exhaust manifold once engine has cooled down.

REMOVAL
- Lift hood to a 90° angle and engage left hand locking lever.
- Disconnect battery ground cable.
- Drain cooling system and engine oil.
- Remove air cleaner assembly.
- Disconnect accelerator linkage.
- Remove the drive belt. Drive Belt
- Remove ignition distributor.





- Detach fan shroud (1) and place over fan.
During installation: ensure clearance to fan.
- Unbolt fan (75), remove together with fan shroud.
^ Tightening torque 25 Nm (18.5 ft lbs)
- Remove cylinder head cover together with spark plug connector and distributor cover.





- Unbolt exhaust pipes at exhaust manifold.





- Unscrew dipstick guide tube at exhaust manifold (arrow).

Accelerator Cable Connection:

- Detach Bowden cable (30) for accelerator control, press plastic guide (arrow) out of its seat in the fulcrum lever (13) to perform this step, and take Bowden cable (30) out of the slot in the fulcrum lever.
- Compress plastic clip (28) and push clip together with Bowden cable to the rear through the holder (16).
During installation: Adjust Bowden cable (30).





- Unbolt strut at intake manifold. To perform this step, unbolt 2 hexagon socket bolts (arrows) on injection engine.
- Detach return spring for throttle body assembly (below intake manifold).





- Detach coolant hose (68) of supply line for heater.





- Detach connector pickup of control cable (arrow) and 4-pin connector pickup (3) at ignition control module.
- Detach cable from reference resistor (Ri 6) (Model 201 only).
- Unbolt terminal TD at the diagnostic connector (X11).
- Unbolt diagnostic connector (X11), unplug grey cable from the TDC pulse generator at the rear of the diagnostic connecton.
- Unplug all connectors and vacuum lines at thermo valves and temperature switches.





- Disconnect vacuum line for brake booster (arrow).





- Lower fuel pressure in the fuel lines by briefly opening fuel filler cap.
- Unbolt fuel lines (379, 380). When detaching the fuel line (380), hold connection to prevent it from turning.

A/C Piping Group Connection:

- On models equipped with air conditioning, unbolt bracket for pipe group (170) of A/C compressor at cylinder head.





- Loosen bottom bolt (49) for alternator fixture.
- Remove top bolt (51), swivel alternator out of the way to the outside (arrow).





- On models equipped with self leveling suspension, unbolt pressure oil pump, place to the side with lines connected (arrows).





- Set engine to ignition TDC of No. 1 cylinder.





- Mark camshaft gear and timing chain relative to each other.





- Check setting marking on camshaft (arrow).





- Unscrew locking nut (40) of the chain tensioner.
^ Tightening torque 70 Nm (52 ft lbs).
During installation: Replace seal (41).





- Hold camshaft gear tight with an open-end wrench (waf 24 mm) for loosening or tightening the camshaft bolt.
- Unbolt camshaft gear and remove. Place timing chain in timing cover.
^ Tightening torque 80 Nm (59 ft lbs).





- Unscrew hexagon socket bolts (arrows) with the pin wrench 116 589 03 07 00.
^ Tightening torque 25 Nm (18.5 ft lbs) (reference value).





- Remove cylinder head bolts in stages in the reverse order of the tightening diagram with the torque wrench insert 617 589 00 10 00 with engine cold.
- Remove cylinder head (51).

INSTALLATION NOTES
- Install in reverse order of removal.
- Clean mating faces on cylinder head and crankcase.
- Replace cylinder head gasket.





- Check the shaft length of the cylinder head bolts.
^ If the maximum length (L) of 122 mm is exceeded, the bolts should be replaced with new ones.
- Oil thread and head contact face of cylinder head bolts and insert.

Accelerator Cable Connection:

- Adjust Bowden cable (30).
- Check for leaks with engine running.

TIGHTENING TORQUES:





Tighten cylinder head bolts in stages in the order of the tightening diagram, beginning with 1.
^ 1st tightening stage: 55 Nm (41 ft lbs)
^ 2nd tightening stage: 90° angle of rotation
^ 3rd tightening stage: 90° angle of rotation
Cylinder head to timing case cover: 25 Nm (18.5 ft lbs)
Camshaft gear: 80 Nm (59 ft lbs).
Locking nut for chain tensioner: 70 Nm (52 ft lbs).
Alternator bolts (49 and 51): 30 Nm (22 ft lbs).
Cooling fan bolt: 25 Nm (18.5 ft lbs)