Hi,

Today, I was working on my 300SL, 1992 with 62000 miles . I had a noise coming from the front of my 104 engine just above the distributor cap. Not knocking nor something rotational. (Bought the car like that). So after some research here and there, I concluded it must be the timing chain guid in the valve cover. Removed the valve cover to inspect and change the guide. Surprisingly the chain was so loose that the guide came off without even removing the tensioner. I replaced that with the new one. Then removed the tensioner and realized it was jammed and the inner part wouldn't slide out. Replaced the tensioner with an OE one too. Put everything back and started the engine. The noise was gone. What a good feeling and how short it was. As soon as shifted to R and D the noise came back. It is defenitely the same type of noise. It's not as continious as it was before and not present when driving.


Is there any possibility that the new tensioner didn't extend out far enough to push the chain? Is there any installation trick that I missed.

Is there any reason or possibility of the chain has streached in such a low mileage?

If the side guides are gone bad, would the noise come still from the top of the engine or it would be clearly on the sides?

I am going to remove the valve cover and see if the chain is still loose or the tensioner has done its job.

By the way the guide rail that I removed had some surface marks but not that bad at all.

Any comments would be greatly appreciated.

Sean