Automotive Air Conditioning Information Forum

Okay....I work res/comm HVAC....
Automotive has its differences.
I just got my Duramax back from Tranny replacement and A/C isn't working.
The compressor wasn't coming on at all....I dumped a coupla cans in and now it's cycling....when running my pressure is at about 40....when not it's in the red.
My whole system was rebuilt about a year ago and I don't wanna fudge it up. Any suggestions on how I should proceed?

Take it back to the shop that replaced the transmission.

Sounds like you don't have real gauges, just the "gauge on a can thing". Here we deal with both low and high pressures at about 1800 rpm, and preach against any leak seal chemicals or refrigerant containing sealers.....

Well said.
If you do HVAC resi/comm you already know you need good gauge readings hi and lo to be able to determine anything useful.
If you used one of those fancy looking recharge cans from the parts store, you are more messed up than ever.....most all have sealer in them ( a BIG no-no, it will destroy your system), and there is no way to purge the attached hose, so you also injected a bunch of air ...
When using the small cans of 134 use only the single ingredient cans that require a can tapper

You have understated the comparison between home/resi and mobile. I do both. Mobile is much much harder than home/resi. MUCH.

I strongly suggest changing your user name. Otherwise, there will be no end to the spam you'll receive.