Necessary preliminary work

Remove TIMING CASE COVER at top left

Crank engine back at central bolt (1) against direction of engine rotation by approx. 90°.

Fig 1: Cranking Engine Back At Central Bolt Against Direction Of Engine Rotation By Approx. 90°

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IMPORTANT: The timing chain on the chain tensioner becomes the tight end on cranking back.
Do not crank engine without chain tensioner or special tool 11 9 900 .

Piston (1) of chain tensioner must be pressed in against oil pressure in housing (see arrow).

Fig 2: Identifying Piston Of Chain Tensioner Pressed In Against Oil Pressure In Housing

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If the chain tensioner piston is retracted over its full length, a 3.5 mm drill bit or a suitable lock pin must be positioned.

Fig 3: Identifying Chain Tensioner Piston Retracted Over Its Full Length

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Release screws (1).

Tightening torque 11 31 5AZ .

Remove chain tensioner (2).

Fig 4: Identifying Chain Tensioner And Screws

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IMPORTANT: Danger of injury!
Chain tensioner is under high preload force.

Chain tensioner arrangement:

Piston
Expansion element
Compression spring
Housing

Fig 5: Identifying Chain Tensioner Arrangement
Courtesy of BMW OF NORTH AMERICA, INC.

Installation note: