11 31 051 Replacing timing chain (N55 up to 3-2012)

Special tools required:

Necessary preliminary tasks

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

Engine removed

Block crankshaft with special tool 11 9 260 .

IMPORTANT: To release central bolt (1), remove special tool 11 0 300 .

Fig 1: Identifying Special Tool (11 9 260)

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IMPORTANT: When central bolt of crankshaft is released, there is no longer a secure connection to timing drive.

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

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

Fig 2: Identifying Crankshaft With Colored Mark

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Vehicles with automatic transmission

Block crankshaft with special tool 11 8 660 .

Fig 3: Identifying Special Tool (11 8 660)

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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: Installing Special Tool (11 8 180)

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IMPORTANT: Before releasing the central bolt, the chain tensioner must be relieved of tension.

Press timing chain with chain tensioner (1) in direction of arrow.

Disconnect timing chain with special tool 11 4 120 .

Fig 5: Disconnecting Timing Chain Using Special Tool (11 4 120)

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IMPORTANT: Breakaway torque of the central bolt > 600 Newton meters
A 3/4-inch tool (large powered square) is required to release central bolt.

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

Tightening torque: 11 21 1AZ .

Fig 6: Removing Timing Chain 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 7: Removing Crankshaft Hub

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Open screw plug (1).

Tightening torque: 11 31 8AZ .

Fig 8: Identifying Timing Chain Screw Plug

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Open screw plug (1).

Tightening torque: 11 11 7AZ .

Installation note:

Replace aluminum screws.

Fig 9: Identifying Timing Chain Screw Plug

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

Tightening torque: 11 31 6AZ .

Fig 10: Identifying Timing Chain Module Bearing Journal

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IMPORTANT: Install special tool 11 4 280 to release the central bolts on the intake and exhaust camshaft adjusters.

Remove INTAKE AND EXHAUST CAMSHAFT ADJUSTERS .

Fig 11: Removing Intake And Exhaust Camshafts Central Bolts

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

Tightening torque: 11 31 5AZ .

Fig 12: Identifying Timing Chain Module 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.

NOTE: Graphic N52.

Fig 13: Removing Timing Chain Module Bolts

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IMPORTANT: Note direction of installation of camshaft sprocket (2).
Collar (see arrow) on camshaft sprocket (2) points to engine.
Incorrect assembly will result in engine damage.

Fig 14: Identifying 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 15: Identifying Timing Chain, Sprocket Wheel 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 16: Inserting Central Bolt With Crankshaft Hub

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Crank engine twice.

Check TIMING .

If necessary, adjust VALVE TIMING .

Replace front CRANKSHAFT SEAL .

Assemble engine.