11 31 090 Installing and removing/replacing chain tensioner piston (N55)

Necessary preliminary tasks :

Remove AIR DUCT

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.

Fig 1: Identifying Chain Tensioner

Courtesy of BMW OF NORTH AMERICA, INC.

Installation note :

Replace sealing ring.

If the chain tensioner is used again, the oil must be drained out of the chain tensioner. Place chain tensioner on a level support and slowly compress.

Repeat process twice.

Fig 2: Compressing Chain Tensioner

Courtesy of BMW OF NORTH AMERICA, INC.

Assemble engine.