Overhaul

Removing and installing timing-case cover

Preliminary work

1. Remove the engine.
2. Remove transmission from engine and suspend it on the assembly support.
3. Drain engine oil.
4. Remove drive belt.
5. Remove coolant hoses in front of the timing-case cover. Don't forget the holder.

Coolant return line on turbo engine, for example

1 - Connection piece on generator
2 - Connection piece screw
3 - Screw, M6 x 20
4 - Coolant return line
5 - Coolant return hose assembly
6 - Holder
7 - M6 screw Aluminum screw; always use new aluminum screws
8 - Clip

6. Remove both valve covers.
7. Remove vibration damper.
8. Remove joint flange behind the vibration damper and do not re-installed old flange.
9. Remove oil pan and oil guide housing.

Information

Component overview

Timing-case cover seals

1 - Timing-case cover
2 - Timing-case cover seal, outer right (fill openings with sealant, see 6)
3 - Timing-case cover seal, inner
4 - Timing-case cover seal, rib
5 - Timing-case cover seal, outer left (fill openings with sealant, see 6)
6 - Sealant application on timing chain housing; Loctite 5900 (000.043.204.35 status 10/08)

Applying sealant (filling openings in metal seal)

1 - When timing-case cover is fitted, apply sealant to joint before fitting valve covers
2 - When timing-case cover is fitted, apply sealant to joint before fitting valve covers

Applying sealant before fitting valve covers

1 - When timing-case cover is fitted, apply sealant to joint before fitting valve covers

20 mm - Length of sealant applied to joint

Tightening sequence for timing-case cover

A - Aluminum screw M6 x 30; timing-case cover to crankcase and cylinder head; always use new aluminum screws
B - Aluminum screw M6 x 55; inner part of timing-case cover to upper part of crankcase and cylinder head; always use new aluminum screws; outer part of timing-case cover to cylinder head
C - Aluminum screw M8 x 55; timing-case cover (chain tensioner position) to upper part of crankcase and cylinder head; always use new aluminum screws
D - The timing-case cover must be level with the lower part of the crankcase (use steel rule or dial gauge)

Chain tensioner, joint flange

1 - Joint flange (oil sealing lip with engine oil); align with sleeve or vibration balancer
2 - Aluminum screw, M6 x 20; always use new aluminum screws
3 - Aluminum screw, M6 x 55; always use new aluminum screws
4 - Sealing ring; always replace
5 - Chain tensioner

Removing timing-case cover

NOTICE
Timing-case cover removed incorrectly
* Risk of damage to seal between oil pan and crankcase
* Risk of engine leaks

-> Always reseal the oil pan when removing the timing-case cover.

1. On turbo engines, remove positive crankcase ventilation completely in front of the timing-case cover. Be careful with connections that cannot be loosened.

One-way couplings for ventilation on turbo engines

1 - Turbocharger/manifold module
2 - Check valve for vent line to oil-mist separator and intake-air distributor.
3 - Full-throttle ventilation one-way coupling => Cannot be refitted. Make sure the markings are positioned correctly with respect to each other during initial fitting.
4 - Full-throttle ventilation one-way coupling to intake manifold => Cannot be refitted. Make sure the markings are positioned correctly with respect to each other during initial fitting.

2. Remove belt tensioner and deflection rollers on the timing-case cover. To do this, lever off the cover and loosen the screws.

Belt drive

1 - Deflection roller
2 - Hydraulic belt tensioner; tensioner at the lever, tensioning roller at the tensioning lever
3 - M8 screw; complete lever on timing-case cover and cylinder head; belt tensioner and timing-case cover at the console
4 - Deflection roller
5 - Dual poly V-belt

3. Unclip vacuum lines from the cable duct if fitted -arrows-.

Unclipping vacuum lines at the cable duct

Releasing cable duct

4. Unscrew fastening screw -1- on the cable duct -2-.
5. Remove chain tensioner.
6. Remove timing-case cover. To do this, loosen all screws in reverse order.

Tightening sequence for timing-case cover

A - M6 screw
B - M6 screw; inner timing-case cover to upper part of crankcase and cylinder head; timing-case cover to cylinder head
C - M8 screw; timing-case cover (chain tensioner position) to upper part of crankcase and cylinder head
D - The timing-case cover must be level with the lower part of the crankcase (use a steel rule or dial gauge)

7. Carefully remove timing-case cover. Lever off gently if necessary (bonded with sealant).

Installing timing-case cover

Information
If cold or excessively low-tempered components are sealed to each other by applying sealant, leaks can occur because of condensed water forming or components distorting. Components must be uniformly at least -> Temperature: 17 degrees C.

Information
* Acetone can be used to clean the sealing faces. Ventilate this for 5 minutes before applying more sealant.

1. Clean dirt and grease off the sealing faces of the engine and timing-case cover.

Information
Carefully apply Loctite 5900 sealant on the timing chain housing in such a way that sealant cannot get into the screw holes when you fit the timing-case cover. Loctite 5900 can increase the friction coefficient of the aluminum screw. The sealant must not overflow.

2. Fit the new metal seals on the timing-case cover. Fill the openings in the metal seals with sealant. Apply sealant at the specified markings on the engine. Apply the sealant in such a way that no excess sealant can expand into the engine when the timing-case cover is fitted (blocked oil ducts).

Applying sealant (filling openings in metal seal with sealant)

Applying sealant (filling openings in metal seal)

1 - When timing-case cover is fitted, apply sealant to the joint before fitting valve covers
2 - When timing-case cover is fitted, apply sealant to the joint before fitting valve covers

3. When fitting the timing-case cover, press the tensioning rail away from the sprocket (cylinder 1) towards the timing chain using a screwdriver (second worker required).
4. Fit timing-case cover straight on without letting it slip out of place.
5. Screw down all fastening screws by hand. At this stage, the screw heads should not be all the way down.

Information
* The timing-case cover must be aligned using a dial gauge or steel gauge.
* The timing-case cover must not project over the lower part of the crankcase. Even the slightest projection must be corrected.
* It must not be less than ( -dimension A- )1/10 mm ( -dimension A < 1/10 mm- ).

6. Press the timing-case cover upwards slightly and tighten the fastening screws (approx. 1 - 2 Nm (0.5 - 1.5 ftlb.) so that the timing-case cover is slightly jammed. Then align the timing-case cover.
7. Align the timing-case cover within 5 minutes and screw it on.

Aligning timing-case cover with a dial gauge

Information
The timing-case cover must not project over the crankcase. The maximum offset is -> Length: 0.1 mm.

1. Insert the dial gauge into the universal dial gauge bracket and position it so that the dial gauge has a preload of about 1 mm.

Adjusting the preload

2. Set dial gauge scale to 0. To do this, place the dial gauge bracket on a completely flat surface (e.g. crankcase flange) and turn the dial gauge scale until the pointer is at 0.

Resetting dial gauge scale

3. Measure offset. To do this, push with the bracket starting from the lower part of the crankcase towards the timing-case cover (the base of the dial gauge bracket is not located on the same component as the dial gauge probe) and measure the offset. The timing-case cover must not be set back by more than 0.1 mm. Even the slightest projection must be corrected.

Measuring the setback distance

4. Align the timing-case covers by tapping lightly with a rubber hammer.

Aligning timing-case cover

5. Once you have aligned the timing-case cover, tighten two fastening screws on the left and right of the timing-case cover base hand-tight. Then check the position of the timing-case cover again using the dial gauge.

Checking position

Securing timing-case cover

Information
The tightening specifications for the basic engine are stored centrally. Tightening torques and assembly instructions for other affected assemblies (e.g. chassis, electrics, transmission or body) or for peripheral engine equipment can be found in the corresponding documents.

1. Tighten the fastening screws to the relevant parameters in the sequence shown.

Securing cable duct

3. Clip in vacuum lines at the cable duct -arrows-.

Clipping in vacuum lines at the cable duct

4. Fit belt tensioner and deflection rollers on the timing-case cover. Fit screws and cover.

Belt drive

1 - Deflection roller
2 - Hydraulic belt tensioner; tensioner at the lever, tensioning roller at the tensioning lever
3 - Screw, M8 x 96; complete lever on timing-case cover and cylinder head; belt tensioner and timing-case cover at the console
4 - Deflection roller
5 - Dual poly V-belt

5. On turbo engines, fit positive crankcase ventilation completely in front of the timing-case cover.

One-way couplings for ventilation on turbo engines

1 - Turbocharger/manifold module
2 - Check valve for vent line to oil-mist separator and intake-air distributor.
3 - Full-throttle ventilation one-way coupling => Cannot be refitted. Make sure the markings are positioned correctly with respect to each other during initial fitting.
4 - Full-throttle ventilation one-way coupling to intake manifold => Cannot be refitted. Make sure the markings are positioned correctly with respect to each other during initial fitting.

Subsequent work

1. Install oil guide housing and oil pan.
2. Fit new joint flange behind the vibration damper.
3. Set the timing. To do this, connect the vibration damper.
4. Fit vibration damper.
5. Install both valve covers.
6. Fit drive belt.
7. Fit coolant hoses in front of the timing-case cover. Don't forget the holder.