11 31 051 Replacing Timing Chain (N51)

Special tools required: 

For the following special tools, refer to ENGINE - SPECIAL TOOLS (N51) .

• 11 0 300 
• 11 4 280 
• 11 4 360 
• 11 4 362 
• 11 5 200 
• 11 9 280 

Necessary preliminary tasks: 

• Remove cylinder head cover  . See 11 12 000 REMOVING AND INSTALLING OR SEALING CYLINDER HEAD COVER (N51) .
• Remove all spark plugs.
• Remove chain tensioner  . See 11 31 090 INSTALLING AND REMOVING/REPLACING CHAIN TENSIONER PISTON (N51) .
• Remove radial shaft seal  at front. See 11 14 005 REPLACING FRONT CRANKSHAFT SEAL (N51) .
• Remove belt tensioner  . See 11 28 020 REPLACING TENSIONING DEVICE FOR ALTERNATOR DRIVE BELT (N51) .
• Remove vibration damper  . See 11 23 010 REMOVING AND INSTALLING OR REPLACING VIBRATION DAMPER (M51) .

Remove fastener (1) in direction of arrow.

Installation: 

Install fastener (1) with bore facing outwards.

Fig 1: Removing Fastener

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Secure crankshaft during entire repair operation with special tool 11 0 300. See Fig 2.

Fig 2: Securing Crankshaft

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Do not remove special tool 11 4 280. See Fig 4.

Fig 3: Identifying Special Tools

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Mount special tool 11 9 280 on hub for vibration damper. See Fig 4.

Release central bolt (1).

Tightening torque. See 11 21 1AZ in 11 21 CRANKSHAFT AND BEARINGS .

Remove central bolt with hub towards front.

Fig 4: Identifying Special Tool (11 9 280) And Vibration Damper

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Open plug (1).

Tightening torque. See 11 31 6AZ in 11 31 CAMSHAFT .

Fig 5: Identifying Plug

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Open plug (1).

Tightening torque. See 11 31 6AZ in 11 31 CAMSHAFT .

Fig 6: Identifying Plug

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Release screw (1) on chain drive at top.

Tightening torque. See 11 31 2AZ in 11 31 CAMSHAFT .

Fig 7: Identifying Screw On Chain Drive

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Release screw (1) on chain drive at bottom.

Tightening torque. See 11 31 3AZ in 11 31 CAMSHAFT .

Fig 8: Identifying Screw On Chain Drive At Bottom

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Remove both adjusting units  . See 11 36 046 REMOVING AND INSTALLING/REPLACING INLET AND EXHAUST ADJUSTMENT UNITS (N51) .

Release screws (1).

Tightening torque. See 11 31 2AZ in 11 31 CAMSHAFT .

Remove timing chain module with timing chain and sprocket wheel upwards in direction of arrow.

Fig 9: Identifying Screws

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Fig 10: Locating Sprocket Wheel

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Pull timing chain (1) upwards until sprocket wheel (2) engages chain guide (3).

Install timing chain (1) and sprocket wheel (2) in this position.

Installation: 

Always keep timing chain tensioned; it is possible for timing chain (1) to jam on chain module (3).

Fig 11: Identifying Timing Chain And Sprocket Wheel

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Install hub with central bolt.

Tighten down special tool 11 5 200 with screws (1). See Fig 12.

Fig 12: Identifying Special Tool (11 5 200)

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Remove belt tensioner  . See 11 28 020 REPLACING TENSIONING DEVICE FOR ALTERNATOR DRIVE BELT (N51) .

Screw in special tool 11 4 360. See Fig 13.

Mount special tool 11 9 280 on 11 5 200. See Fig 13.

Support special tool 11 9 280 on special tool 11 4 362. See Fig 13.

Special tool 11 0 300 secures crankshaft. See Fig 13.

Tighten central bolt (1) to jointing torque.

Tightening torque. See 11 21 1AZ in 11 21 CRANKSHAFT AND BEARINGS or 11 21 CRANKSHAFT AND BEARINGS .

Mark central bolt and hub with paint.

Fig 13: Identifying Special Tools

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Apply stroke of paint (1) for torsion angle tightening to tool.

See illustrations.

Fig 14: Identifying Paint For Torsion Angle

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Tighten central bolt with two persons.

Tightening torque. See 11 21 1AZ in 11 21 CRANKSHAFT AND BEARINGS or 11 21 CRANKSHAFT AND BEARINGS .

Install both adjusting units  . See 11 36 046 REMOVING AND INSTALLING/REPLACING INLET AND EXHAUST ADJUSTMENT UNITS (N51) .

Install chain tensioner  . See 11 31 090 INSTALLING AND REMOVING/REPLACING CHAIN TENSIONER PISTON (N51) .

Fig 15: Identifying Special Tools

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Crank engine twice.

Check timing  . See 11 31 505 ADJUSTING CAMSHAFT TIMING (N51) .

Assemble engine.