11 31 090 Installing and removing/replacing chain tensioner piston (N20)

WARNING: This page is about a different variant/trim than selected.

Necessary preliminary work:

Remove ENGINE VENTILATION LINE .
Drain coolant.

Unlock coolant hose from expansion tank (1) and pull off.

Fig 1: Identifying Expansion Tank

Undo coolant hose (1) from thermostat.

Fig 2: Identifying Thermostat Coolant Hose

Unlock and detach coolant hose (1).

Fig 3: Identifying Coolant Hose

Release screws (1).

Tightening torque: 11 65 4AZ.

Fig 4: Identifying Chain Tensioner Piston Screws

Raise vacuum unit (1) slightly.

Release chain tensioner (2).

Tightening torque 11 31 7AZ .

IMPORTANT: Have a cleaning cloth ready. A small quantity of engine oil will escape after the screw connection has been released.
Make sure no engine oil runs onto belt drive.

Fig 5: Identifying Chain Tensioner

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.

Fig 6: Compressing Chain Tensioner

Assemble engine.