My 79 450 SLC has a leaking cam chain tensioner. It is leaking around the HUGH nut at the end. The mechanic I have used for years with my Mercedes cars, told me the tensioner is probably OK. But the HUGH nut at the end has a seal, similar to a large O ring. He suggested to back off the nut one or two turns and re-torque to spec (90 ftlbs). This SHOULD stop the leak. I inquired at Mercedes and to replace the tensioner it would cost $375 for the tensioner and 2 hours labor, as the manifold and the car, yes the cat on this engine is on the sides of the engine. Those crazy germans.

Anyone have any experience with these tensioners? I have been told if they go, they can cause the timing chain to fail and bye, bye engine.

Thanks in Advance

 

just replace the aluminum seal washer.

lots of them are leaking.

 

Your mechanic is right. Do ensure that the internal piston does not move when you remove the retaining plug (which is the bit you see). It should not if you release the plug gently and don't let it 'spring' out when you undo it.

The plug is what holds the tensioning spring, so this will be visible when you undo it. Then either grab a new washer and install or just clean and check the old ones mating surfaces for any signs of damage and refit.

Having said all that, I have only worked on 6 cylinder MB's and not V8's. I do not believe the design will greatly differ, however. Just be gentle and take note of what comes out and then put it back in the same order!