A/C Help - Please - Benzworld.org

damccord · 06-09-2008, 02:00 PM

Looking for some help/input on an A/C problem on my 91 190E/2.3. Recently acquired the car with 123K. A/C did not run, as if was low on freon. The car has been converted to R134A at some point in time. I've attempted to recharge the system in an attempt to "find" any leaks and issues with the system.

Have jumped accross the pressure switch to get the compressor to run. In attempting to fill the system it starts to pull the freaon ( can gets cold, etc...) and appears to start accepting the frean. After a few minutes, the compressor stops running/clutch disengages. When the charge hose is disconnected there is a significant amount of pressure present and the schrader valve apparntly doesn't close, as all the freon leaks back out of the system immediately. At that point the compressor will then start to run again and it will go back through the same turn of events. It appears like the system is building up pressure and freon is not flowing freely, which locks the compressor up? Possible blockage in the system ? maybe the Receiver/Dryer? Any thoughts or ideas? Thanks, could use the A/C......it's getting warm and summer is here.

GPost · 06-09-2008, 02:28 PM

Are you using the correct valve on the left fender area? Also, obviously, the valve is bad. The conversion fitting is probably bad and holding down the schrader valve. There should be no need to "jump" the compressor to start it. When you start putting in the freon, when it gets enough pressure, the compressor will start. It will cycle shortly at first then get better. How much are you putting in?

gonzalr1 · 06-09-2008, 04:04 PM

YO, I know a bit about a/c systems--to start off did you put a vacuum pump on system before you added freon gas,if not your a/c system will not operate properly.My cousin had same problems you have,I realeased all of the freon and did a vacuum ,then added freon and wala! a/c working properly! If you redo everything again,i recomend to change a/c valve if possible. note: you say system was low on freon,but do we know if past owner ever had the a/c properly working? Maybe he or she also put freon gas without putting a vacuum on it!