Valve Cover: Service and Repair
WM 158219 Removing and installing cylinder head cover - engine removed
Preliminary work for removing cylinder head cover
Preliminary work for removing cylinder head cover
1. Remove engine.
2. Remove rear muffler.
Removing cylinder head cover - engine removed
Removing cylinder head cover - engine removed
Caution
Risk of damage due to particles of dirt.
Danger of material damage due to blocked oil bores/oil ducts.
- Absolute cleanliness is essential when working on the engine.
- Lay removed engine parts on a clean base and make sure to cover them.
- Use the cover for dust protection when fitting the engine NR.165 on the engine assembly support.
Information
Replace O-ring on the oil suction pump or tandem pump.
Cylinder row 1-3:
1. Remove cover plate for ignition coils -1-. Unscrew two M6 x 16 Torx screws and remove cover plate.
Cover plate and support for rear muffler
2. Remove holder for rear muffler -2-. Pull off cable plug for ignition coil cylinder 2 (side 4-6 cylinder 5) and cable plug for solenoid hydraulic valves. Unscrew the four Torx screws: intake side, two M8 x 30, exhaust side, two M8 x 25, remove support.
3. Remove ignition coils -1-. Pull off remaining ignition coil cable plugs. Unscrew two M6 x 25 Torx socket screws, pull the ignition coils out of the spark-plug recess.
Hydraulic valves for camshaft adjustment and ignition coils
4. Remove support and retainer plates (with integrated seal) for the solenoid hydraulic valves (camshaft timing and valve lift control) -2-. If the valves do not have to be replaced, these can remain in the cylinder head (side 1-3 both, side 4-6 camshaft timing only)
5. If the solenoid hydraulic valve is removed for camshaft timing, the oil strainer -1- must be checked for damage and contamination, and replaced if necessary.
Oil strainer hydraulic valve NVS
6. Remove oil suction pump. Unscrew four M6 x 20 Torx screws (micro-self-locking), remove oil suction pump, replace O-ring and screws.
Caution
Damage when levering off the cylinder head cover.
Cast lugs could break.
- Perform work steps carefully and gently.
Information
The coated screws for the bearing surfaces of the camshaft in the cylinder head cover must be replaced when installing.
7. Remove the cylinder head cover. Unscrew 20 M6 x 30 Torx screws from the cylinder head cover. To loosen the cylinder head cover, raise the cover carefully at the two protruding cast edges with a screw driver or mounting lever. Remove cylinder head cover.
Lifting cylinder head cover from above
Lifting cylinder head cover from below
8. Remove the plastic cap.
Information
Make sure that it is cleaned thoroughly and that residual sealing compound is removed completely. Even the smallest particles can block up oil bores.
9. Clean the sealing faces on the cylinder head cover and cylinder head thoroughly (use brass - or nylon brush, a clean and lint-free cloth soaked in acetone). All residual sealing compound in the cylinder head and on the cover must be removed before assembling.
Additional work steps on the cylinder row 4-6:
Loosen ground cable on the cylinder head, to do this, unscrew on M8 Torx screw and remove the cable.
Unplug two cable plugs for the oil pressure switch.
A tandem pump is installed on side 4-6 instead of the oil suction pump. Pull off the vacuum line on the pump. Replace O-rings and micro-self-locking screws.
Because of the small distance to the exhaust manifold, the valve lift control valve must be removed, so that the cover can be removed and installed without difficulty. Pay attention to the spring element.
Solenoid hydraulic valve, valve lift control
Installing cylinder head cover - engine removed
Installing cylinder head cover - engine removed
Caution
Risk of damage due to particles of dirt.
Danger of material damage due to blocked oil bores/oil ducts.
- Absolute cleanliness is essential when working on the engine.
- Lay removed engine parts on a clean base and make sure to cover them.
- Use the cover for dust protection when fitting the engine NR.165 on the engine assembly support.
Information
The coated screws for the bearing surfaces of the camshaft in the cylinder head cover must be replaced when installing.
1. Insert three new seals for the spark-plug recesses.
Spark plug slot seals and solenoid hydraulic valves
Only the following sealants may be used to seal the cylinder head cover:
"Drei Bond" silicone - type 1209
Loctite 5900
2. Prepare cylinder head cover for assembly. Apply a thin bead of sealant on the cylinder head cover (not higher than 1.5 mm).
Sealant application cylinder head cover
3. Coated screws on the camshaft bearing surfaces -1- must be replaced.
Screws for camshaft bearing surface
4. Place the cylinder head cover carefully onto the cylinder head. The bead of sealing compound must not be wiped off or interrupted.
5. Position 20 Torx screws (eight of these should be new, coated screws) on the cylinder head cover and tighten according to the specified tightening sequence. Only lightly screw in the two screws in the area of the oil suction pump/tandem pump. They will be tightened after the pump is assembled. - Tightening torque: 9.5 ftlb.
Tightening sequence, cylinder head cover
6. Position a new cap [diameter] 45 mm (brown) on the bore of the intake camshaft on the pulley side and tap it gently into place with a plastic hammer (dry mount).
7. Insert two new caps (green) into the small bores on the clutch side. Tap it in with a plastic hammer (dry mount).
Information
Replace O-ring on the oil suction pump or tandem pump.
8. Mount the oil suction pump or tandem pump with four new, micro-self-locking Torx screws -1-. Replace O-rings on the pumps and the vacuum line -2-. Lightly grease O-rings with Optimol MP3. - Tightening torque: 7.5 ftlb.
Tandem pump side 4 - 6
9. Tighten the two screws on cylinder head cover in area of oil suction pump/tandem pump. - Tightening torque: 9.5 ftlb.
10. Insert the solenoid hydraulic valve, valve lift control on cylinder 4-6 with a new O-ring.
Note installation position (plug connection is horizontal).
11. Push on two new retainer plates on the solenoid hydraulic valves on each cylinder row. Position support and tighten with two M6 x 20 Torx socket screws. - Tightening torque: 7.5 ftlb.
Holder for solenoid hydraulic valves
A: support for camshaft adjustment valve (camshaft timing)
B: support for valve lift adjustment valve (valve lift control)
Retainer plate with integrated gaskets (identical parts)
Installation position for solenoid hydraulic valve retainer plates
1-camshaft timing retainer plate
2-valve lift control retainer plate
12. Insert ignition coils into the spark-plug recesses. Position and tighten two M6 x 25 Torx socket screws per ignition coil. - Tightening torque: 7.5 ftlb.
13. Position support for rear muffler with four Torx screws: intake side, two M8 x 30, exhaust side, two M8 x 25, then tighten to the specified torque. - Tightening torque: 17 ftlb.
14. Plug in cable plugs for ignition coils and magnetic hydraulic valves. Secure the cables of the hydraulic valves in the sheet metal clips.
15. Install cover plate, position and tighten two M6 x 16 Torx screws. - Tightening torque: 7.5 ftlb.
Cylinder side 4-6:
16. Connect the two cable plugs on the oil temperature switch.
17. Fasten ground cable on cylinder head with M8 Torx screw. - Tightening torque: 17 ftlb.
Subsequent work after installing cylinder head cover
Touch up for installing cylinder head cover
1. Fit rear mufflers.
2. Install engine.