1987 300D A/C Thoughts...
 

Well... I think I've finally solved the mystery of the A/C problem with my wife's 300D. For the past 4 months, the compressor has kicked out on a fairly regular basis. It seemed to get worse when the car was accelerated rapidly. I followed all of the steps on the forum... cleaned the Klima relay, checked the OVP, fuses, clutch gap, cleaned the clutch, etc... Well, in the end it turned out that I was having some type of failure with the belt tensioner pulley. It didn't show any outward signs of failure, but when replaced, I could tell the bearing was failing... It just didn't spin very well... I could feel some resistance. Now, the lever, pulley, spring and shock had been replaced about 30k ago and I couldn't believe the pulley had failed. After replacement, everything has been perfect and the system has been working as it should. Whew... I was really starting to worry about other A/C issues that can crop up... I just wanted to add an additional angle to our A/C diagnostics and see what everyone else thinks.

Just in time for winter. :D


Glad you found the problem.

Yeah.....good timing.. One good thing, however, the A/C sure makes a difference when the cabin tends to fog up on the cold nights... My wife loves having the defrost button which auto-activates the A/C. ;)

Ok guys.. my 1987 300D A/c is back to "intermittent" mode and I noticed that the tensioner bearing doesn't look exactly "perpendicular" any longer. I also notice some slight rubbing on the crank pulley and am wondering what is up with this. Could my tensioner bearing fail in only 12k miles since replacement? Right after I replaced it, everything was perfect with the A/C and now it looks to be failing again... Any thoughts..... :(

Did you replace it with aftermarket or dealer parts? The dealer tensioner shock for OM603 motors is a LOT stiffer than the aftermarket ones!

Speedy, the parts I used are from Phil... Febi I think.

I don't remember the specific details, but Dave M (gsxr) informed me that dealer belt tensioner shocks are of superior quality to the Febi ones, as strange as that may seem! Dave, can you chime in here? :cool: