Strange W210 AC behavior - PeachParts Mercedes-Benz Forum

98biobenz · #1 06-15-2007, 01:52 PM

I just had that same problem with the vent temps. It turned out to be a leaking evaporator. It was expensive to replace but seems to be holding temp now. You need to fill system with die to ck for leaks and also use a snooper in the vents to ck for r134 loss...

david s poole · #2 06-15-2007, 05:41 PM

after reading all through this thread it is my opinion that you have two probs.[1] bad heater valve [2] low freon charge[hissing noise and low side pressure readings big clues] replace valve and add freon [not too much] easy check is low pressure at 35-40psi [with in car temp at about 75-80f] and high side at about 250psi slowly going up and bringing on high fan which swings it back to 225psi.next hold engine rpm's at 1500-2000 and make sure high side does'nt climb above 325psi.