Suction line is the larger line that goes to the compressor. What you sdescribe sounds normal. I am just very surprised youre getting temps in the 30's.

Sorry friend, 25 years of commercial and industrial hvac and Im stumped!

Good luck!

 

Ok. I will check it. I don't know why it is THAT cold either. I just know that with it on Max Cold and full fan that it turns the truck into a freezer. Cold enough that I could start to shiver at times and have to turn it all the way off. Now I just need a flat white paint job inside and out and it will be a freezer! LOL

Well the problem does seem external to the A/C system itself. It seems that the system is cooling as it was designed to do, but the issue is the air delivery to the interior. Since the controls that direct the flow from the A/C system are vacuum controlled and the vacuum source is the engine, the problem is probably somewhere between the engine vacuum port and the A/C actuators. I think that the tubing needs an inspection and possibly a replacement. The A/C seems like it is working properly, but getting the air from the HVAC box to the cabin is the issue when the engine is revved and the vacuum pressure drops because of a leak somewhere. It can't be on the engine since the intake manifold gaskets are only 2 years old and there are no coolant leaks anywhere. Likely tubing or something else. I think I can solve part of the possible problem and reduce the failure points by cutting/plugging the tubing going to the transfer case and vacuum actuator (Posilok made all that obsolete and unnecessary) since those are no longer used and might only serve to pull trans fluid into the lines if the transfer case ever overfills.