11 31 051 Replacing timing chain (N55) - from March 2012

Special tools required: 

• 11 0 300
• 11 4 280
• 11 8 180
• 11 8 660
• 11 9 260

Necessary preliminary tasks: 

• Remove CYLINDER HEAD COVER .
• Remove all SPARK PLUGS .
• Remove CRANKSHAFT RADIAL SEAL at front.
• Remove TENSIONING DEVICE for drive belt.
• Remove VIBRATION DAMPER .
• Check TIMING .
• Remove SEALING COVER for vacuum pump.
• Remove SEALING CAP of chain tensioner for oil pump.

Engine removed: 

Block crankshaft with special tool 11 9 260 .

Fig 1: Blocking Crankshaft And Releasing Central Bolt

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Mark position of crankshaft using a colored mark (1).

This will make future insertion of special tool 11 0 300 easier.

Fig 2: Marking Position Of Crankshaft

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Vehicles with automatic transmission: 

Block crankshaft with special tool 11 8 660 .

Fig 3: Blocking Crankshaft With Special Tool (Vehicles With Automatic Transmission)

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Vehicles with manual gearbox: 

Attach special tool 11 8 180 to manual transmission with existing transmission bolts (1).

Block crankshaft in direction of arrow with special tool.

Fig 4: Attaching Special Tool (11 8 180) To Manual Transmission

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Carefully press tensioning rail (1) with a suitable screwdriver (2) in direction of arrow.

As the oil pressure in the chain tensioner can only be drained pulsating, the tensioning rail (1) must be pressed several times.

Fig 5: Pressing Tensioning Rail

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Press the tensioning rail (1) and hold down.

Fix chain tensioner piston in position with a suitable lock pin (2).

Fig 6: Securing Chain Tensioner Using Lock Pin

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Release central bolt (1) with 3/4-inch tool (2).

Tightening torque 11 21 1AZ .

Fig 7: Releasing Central Bolt

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Remove CHAIN TENSIONER .

Screw in vibration absorber screws (1).

Move hub (2) on crankshaft forward in direction of arrow to remove.

Fig 8: Removing Crankshaft Hub

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Open screw plug (1).

Tightening torque 11 31 8AZ .

Fig 9: Identifying Screw Plug

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Open screw plug (1).

Tightening torque 11 11 7AZ .

Installation note: 

Replace aluminium screws. 

Fig 10: Identifying Screw Plug

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Release bearing journal (1) from timing chain module on cylinder head.

Tightening torque 11 31 6AZ .

Fig 11: Identifying Bearing Journal

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Remove INTAKE AND EXHAUST CAMSHAFT ADJUSTERS .

Fig 12: Releasing Central Bolts On Intake And Exhaust Camshaft Adjusters

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Release bearing journal (1) from timing chain module on crankcase.

Tightening torque 11 31 5AZ .

Fig 13: Identifying Bearing Journal

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Release bolts (1) from timing chain module on cylinder head.

Tightening torque 11 31 4AZ .

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

Fig 14: Removing Chain Module with Timing Chain And Camshaft Sprocket

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Fig 15: Identifying Collar On Camshaft Sprocket

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

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

Installation note: 

Always hold timing chain (1) under tension. Timing chain (1) may jam on chain guide (3).

Fig 16: Identifying Timing Chain, Sprocket, And Chain Guide

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Insert central bolt (1) with hub for crankshaft.

Tighten down central bolt (1).

Tightening torque 11 21 1AZ .

Install INTAKE AND EXHAUST CAMSHAFT ADJUSTERS .

Install CHAIN TENSIONER .

Fig 17: Tightening Central Bolt

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Crank engine twice.

Check TIMING .

If necessary, adjust VALVE TIMING .

Replace front CRANKSHAFT SEAL .

Assemble engine.