MRPerformance,
I just had the shop check for the refrigerant level and they said it's full since i had it filled up last year. I asked them to check the A/C system and they said they couldn't find the problem. I've taken it to the mercedes dealer as well as private shops and none of them seem to figure this problem out. However searching the posts I've noticed that quite a few w124 owners have had this problem.
Any other ideas ?
thanks for everyone's help here.