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.

Installation note:

Replace sealing ring.

Fig 1: Identifying Chain Tensioner

Courtesy of BMW OF NORTH AMERICA, INC.

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.