A/C Issue

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by jessb_55, May 28, 2012.

  1. jessb_55

    jessb_55 New Member

    System builds too much pressure prior to the finishing of adding all required freon (amount listed), also makes belt squeal and belt tightener slap when revving the engine. Rebuilt A/C pump has 10k miles on it. Took all A/C lines lose and blew air threw them along with through both evaporators. Also replaced dryer can and both orifice tubes/screens, and expansion valves in the rear unit. Also blew out the front condenser air passages for bugs.

    It's a 2001
  2. kw70chevy

    kw70chevy Member

    how much pressure on the high side 250 and the low side 45.did you put the right amount of comp oil in it cause it sounds like your compressor trying to lock up to me.
  3. janikphoto

    janikphoto Rockstar 3 Years 100 Posts

    You should not throw your truck parts, no matter how mad you get! Seriously, though... I knew you meant to type through. I just couldn't help making the joke. If it is building up too much pressure, there is supposed to be a pressure sensor on a/c systems, and your unit might be bad. Also, why didn't you change out the front expansion valve, too? That is the weak point on many modern a/c systems...
  4. jessb_55

    jessb_55 New Member

    still no luck

    so I did replace the expansion valve in the rear, also just purchased a new condensor, going to try that next I guess.. Still at a loss as to why once I hit about 2 lbs of freon the pressure gets to high and I can't finish adding the required amount.
  5. jessb_55

    jessb_55 New Member

    Janikphoto- Yes your right I shouldn't be throwing things but I'm gonna have to continue to do so if i can't get this working. As far as the front expansion valve, as far as I know there isn't one in the front, just the orfice tube, I thought the back had both? What is this pressure sensor you speak of ? :)
  6. bazar01

    bazar01 Epic Member 5+ Years 100 Posts

    What are the system pressures on the high and low side? The pressure switch is there for protection, it will not cause a high pressure condition.
    High pressure condition occurs when there is a restriction in the lines, it could be form an expansion valve not opening on demand, an orifice that is blocked (unlikely for a new one), condenser coil not getting enough airflow across the coil due to a weak clutch fan or electric fan or a plugged drier (unlikely for a new one).

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