The chain tensioner (244) is screwed into the cylinder head on the right side. Engine oil is supplied to the chain tensioner under pressure through a hole in the cylinder head.
The chain is tensioned by the force of the compression spring (230) and the oil pressure in the tensioner. The pressure of the pin (233) on the control bus (215) is maintained constant by means of the check valve (227/228) and the pressure limiting valve (227/231), i.e. it does not depend on the oil pressure in the engine.
(Publication reprinted from this resource: MERCEDESMAN.ru)
Removal
Unscrew the chain tensioner by the hex head (235) from the cylinder head.
Control
1. Place the chain tensioner with the pressure pin in SAE 10 engine oil. The oil level should be slightly above the rim of the tensioner hex head. Press the pressure pin 7-10 times with a press.
2. After filling with oil, the tensioner should compress slowly, evenly and with great force. Otherwise, replace it.
Installation
Caution! Only install the chain tensioner when it is filled with oil.
Install the chain tensioner using a new sealing gasket and tighten the mounting bolts to 80 N·m (60 ft·lbs). The pressure pin should be in contact with the tensioner slide lug.