OM603 timing chain tensioner

[sixto]

To remove the tensioner as part of removing the camshaft, do I turn the bigger outer nut or the smaller inner nut? The CD manual isn't specific that I can see.

Thanks,
Sixto
91 300SE
87 300SDL

[engatwork]

I remove the bigger outer nut. The inner nut system has an arrangement in it that will prevent the tension from "coming back" so it will not do much good to just back off on the inner nut. Once it is on the bench you can remove the inner nut and then push the pin through (toward the chain if it was still in the car). The pin will then come out. During reassembly install the big outer nut and then install the inner nut. Install the big nut with the pin already in place in the fully retracted position. Then when you install the inner nut it will push the pin toward the chain. Tighten the inner nut to torque and once you crank up the engine the oil pressure will take up anymore slack that may be there. You do not want the pin all the way extended toward the chain when you bolt the tensioner in. Make sure you have a new gasket (crush ring) for it when you put it back together.