timing tensioner for 240 d 1975 (the saga continues)

good evening, the saga continues, I was doing a valve adjustment on my 1975 240 d which I have posted before, low compression. I was checking the valves and noticed that the tension on the timing chain was not working. I noticed a lot of free play in the chain?? could this be causing the timing to jump and therefore cause low compression????????? i was able to check the valve and all were within specs. I would appreciate any suggestions on the tensioner. It appears i have to take off the air cond compresser and perhaps the drain the system just to find the bolt????? Again, would apprecaite any help on this subject. tks, Don