11 31 090 Installing and removing/replacing chain tensioner piston (S55 engine)

Necessary preliminary work:

Release chain tensioner (1).

Tightening torque: 11 31 7AZ .

IMPORTANT: Have a cleaning cloth ready. A small quantity of engine oil will emerge after the screw connection has been released.

Make sure no engine oil runs onto belt drive.

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Installation note:

Replace sealing ring.

If the chain tensioner is reused, its oil chamber must be drained. Place chain tensioner on a level support and slowly compress.

Repeat process twice.

Courtesy of BMW OF NORTH AMERICA, INC.

Assemble engine.