03 Ex 6.0 A/C

[springhillracer]

alright, so Im going to burn my excursion...A couple weeks ago, I noticed the a/c in my truck at times would blow warm air. One day I was in the truck and I heard a noise and my ac started blowing warm, the noise stopped and it was cold again. I run an auto shop, brought my truck in and the a/c clutch was slipping. Ok, it has 111k on it, time for a new compressor. I swapped the compressor, orfice tube and accumulator. The orfice was clean as can be. I vac the system for 45 minutes, charge 4.25 pnds and my high and low side were through the roof. 350-400 and 70-80 on the low side. Figured I got a bad compressor, it happens. Warrantied the parts, flushed the condenser, which was clean. No medal in system. Evac and recharges again....same thing. Same pressures. My fan clutch seems to be working ok, but just to be safe I installed a aftermarket fan onto the condenser. This did not help AT ALL. Still high pressures. Do I have another bad compressor? I have done plenty of a/c jobs and this is driving me nuts. I know with the added ac in the rear and just over 4pnds my pressures are gonna be high, but not this damn high. My suburban has rear ac also and at 4pnds of freon its around 275-300 and 50....WHAT NEXT? Do I have a weak fan clutch? I was going to mist the condenser and see if this helped at all. Any thoughts?

[2006PSDSD]

How hot is it outside? It sounds more like the ambient air is just so hot that it has the system load high

Is the air cold? Drive the truck around and make sure the air is cold so you have goo airflow over the condenser

What is your superheat running?

[Acidsniper]

Just curious. Did you have a micron gauge hooked up to the system at all? What was it reading? I believe the Excurs with rear air are 4lbs 4oz system capacity so your 4.25 lbs was right on the money there.

I'm taking it the 50 at 4lbs was your low side pressure at idle? That's still a little high, should be around 30 - 35 at idle. While the clutch is engaged spray the condensor with a water hose, does that drop the pressure down to the 30 - 35 range? If so, since you've replaced the compressor twice now my next guess would be the fan clutch. What's your vent temp with the A/C running? Based on ambient air it should be in the 50's - mid 60's range.

Sounds like you're on the right track tho.

Did some quick googling and there's a rear expansion valve behind the jack storage compartment (remove the compartment to get to it), did you replace that as well? There's also a gray vaccum line on the 250 PSD's that runs from behind the fan to the top of the motor by the passenger side valve cover, is this connected?

[a2elvis]

Restricted condensor maybe bad fan clutch...