190E 16V Timing Chain Tensioner

[Jim Herold]

I just replaced the timing chain tensioner on my 1987 190E 16V with the upgraded model available from Mercedes. Prior to the change I checked chain stretch at something very close to only 1 degree. The chain was tight over and between both cam sprockets with the original tensioner and the engine turned off. The chain is much looser now between the cam sprockets with the new tensioner installed. I have not turned the engine over until I understand why the chain would be looser.

Could the chain have jumped a tooth on one of the camshaft sprockets when the old tensioner was released? If yes, I would guess most likely on the exhaust cam since it sits right above the tensioner. Does the upgraded tensioner work with hydraulic pressure, in which case I would have none since the engine has not been started with the new tensioner installed?

Any information would be appreciated.

Jim Herold