Question on a 95 Suburban AC problem

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by pestman, Apr 10, 2014.

  1. pestman

    pestman New Member

    Hello I am hoping someone here might have experienced this issue i am having. So a few days ago my truck made this high pitch whistle i guess you would call it, the best way i can describe it is when you get a large balloon and pinch the bottom tight and stretch it only allowing a little air to escape that high pitch noise. It did it while running for a few times I isolated It down to the ac unit, I pulled the power connector off and have not experienced it since. The noise does not happen all the time and sometimes I can just drive it around a few blocks come home shut off the engine and than it does it.

    A little background on the vehicle I am not the original owner it has 225,000 miles 1995 suburban and i believe original ac unit.

    Thank You
    Aaron Wilson
  2. bazar01

    bazar01 Rockstar 100 Posts

    If it is coming from the ac unit, the only component that will duplicate the balloon high pitch noise while the unit is on is the orifice tube. If the truck still has the original ac, most probably the screen on the orifice is slightly plugged allowing a small passage of refrigerant. If the orifice gets completely plugged up, the componenet on the high pressure side might get compromised due to overpressure.
    You can either drive it till it quits (expensive repair later) or get the system opened up, orifice screen and drier replaced, evacuated and recharged.

    Evaporator fans also make a high pitch noise when the bearings dry out. Have you tried just turning on the inside fan with the ac compressor off and hear the same noise?
  3. pestman

    pestman New Member

    I can run the heater and defrost with the the fan at any setting and i do not get the noise. The noise will only show up if i plug the ac power connector in and run the defrost or ac.

    Thank you for your advice i will start working on fixing your suggestions.

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