A/C pressures 2004 Denali

[spyderrider]

So, today I had my shop do a quick vac and recharge of my AC in my Denali. We recovered 2.26 lbs and according to the sticker, the truck with front and rear AC takes 2.7 lbs, so .5 lbs low. Not bad considering. Truck held its vacuum, so I charged it to factory specs. After that was done and the machine still connected, truck running with both front and rear blowing, high side pressure was 250 and low side was 100. Temp outside was 85 degrees. From all that I know, those pressures are too high, so I pulled .5 lbs back out, now i'm at 200 high and 75 low.

 

[rockola1971]

Low side was indeed too high. Should have changed the orifice tube while the system was evacuated! They are $4 cheap insurance. Could have the rear TXV sticking. Hows the discharge temp at the rear vents? Always do ALL test on a/c with both front and rear running max. Snug up schrader valves, they are key culprits for leaks. I always replace them when I have the system open. Cheap insurance.