Hey all,

I have a 2002 Chevy express 3500 with about 90,000 miles on it. Midway through my road trip this month the a.c. crapped out. We were driving along and heard a loud hissing sound, that sounded like it was coming from right under the driver's seat. It sounded like pressure being released or possibly a vacuum sucking. The sound lasted about 2 seconds, but recured about 5-6 times. Immediately after, the AC was blowing warm. Does anyone have any ideas what it could be?

We had a mechanic look at it. He hooked it up and put a vacuum on the system looking for leaks but there were no leaks, so he recharged it for us. Hard to tell if we lost refrigerant because our a.c. is blocked off midway to the rear a.c. because the rear a.c. was removed, so it has a different amount than either a van with just front or front&rear, but the amount seemed about right. There were also no obvious leaks.

I just checked to see if the blend doors were working and they seem to be working fine.

​​​​​​Im not really sure where to start looking, because I feel like it's related to that sound I heard immediately before it stopped working.

Thanks in advance!

 

the ac lines to the rear that were chopped off probably leaked.