A/C Ex valve or drier? Or charge? Help, it's hot! - Page 2 - PeachParts Mercedes-Benz Forum

pdrayton · #1 05-10-2008, 03:54 PM

Yep, it's another AC question....

I've read up on the issues but can't find mine amongst them.

The problem is the ac has stopped cooling. It's an 83 240D W123 running on R12. Has been working fine for the past couple of years. Now it works for a short time and then quits. The compressor is still running but the air temps aren't dropping.

There were bubbles in the drier, and the low side was at about 2bar (22psi), while the High is stuck at about 10bar (150psi?). Manual says it should be 3-4 bar low side and 22bar high side while running at 90F ambient.

I added 12oz more R12 and the bubbles are gone. There's acutally no visible flow in the drier, but it could be it is so smooth now I can't see it.

But the high side pressure doesn't look right. It is basically stuck at about 10 bar (should be 22bar). Even when I switch the car off, the high stays high at about 10bar and the low at about 2.

Does that mean the expansion valve is stuck closed? I looked at the exValve and it is cold and has condensation on it. Is it supposed to? I tapped it with a hammer to try and loosen it up if it was stuck, but no joy.

IS that a correct diagnosis - stuck closed expansion valve? If not, what else could it be? And if it is the Ex Valve, is there any way to encourage it to work again without discharging my system? I don't have any R12 left and I don't want to go to R134a unless I have to.

I'm in florida and it's already 90 something degrees! HElp!