Timing Chain Tensioner: Service and Repair

Removal and installation of chain tensioner






Turbocharged engines:
Detach boost air hose (2) to valve body.
Remove chain tensioner (1),
Replace seat and install chain tensioner filled with SAE 10 engine oil.
Torque to 80 Nm.

Note: Chain tensioners which are the subject of problems should be replaced complete.

Filling chain tensioner with engine oil:
Place chain tensioner with the plunger bolt downwards in SAE engine oil until over the collar on the hexagon. Press plunger up to the stop 7 - 10 times slowly with the aid of a press or power drill.
It should be possible to compress the chain tensioner quite slowly, evenly and with little effort after filling with oil.

Note: A modified valve disk (231) has been installed in the chain tensioner since 08/84 in order to limit to peak pressures of the chain tensioner on the tensioner rail.





225 Sealing plug
226 Aluminium gasket A 25 X 30
227 5 mm dia. ball
22B Ball guide
229 compression spring
230 compression spring
231 Valve disk
232 O-ring
233 Plunger
233a Filler piece
234 compression spring
235 Housing
236 B 16 snap ring
a Supply bore from cylinder head
b To oil pan

A Former version
B Current version




d1 32mm
d2 27mm
A Previous version
B Revised version

The outer diameter of the sealing surface on the chain tensioner housing has been enlarged by 2 mm since 07/87 making it necessary to install a sealing ring (237) with dimensions of 27 x 32 mm (previously 25 x 30).
This modification prevents the formation of burrs on the sealing ring (picture, circular cut-out) when tightening the chain tensioner.
This chain tensioner can also be built into vehicles of earlier manufacture.

Special Tools:

Commercially Available Tools: