Loud A/C compressor

Discussion in 'General Chevy & GM Tech Questions' started by TJbear, May 24, 2010.

  1. TJbear

    TJbear Rockstar 100 Posts

    Been noticing the a/c compressor in my truck is making a loud "whirring" noise that increases in intensity with RPM. It seems to be louder the higher the heat load is. I'ts hard to describe the noise. It's not the clutch.

    A/C is working great otherwise, it is ICE cold. Think it needs a little oil?? Worn out? I thought it might be overchaged from the shady used car dealer I bought it from but I don't think it would be working as well as it is if that were the case.
  2. sharpshooterusmc

    sharpshooterusmc Rockstar 100 Posts

    i had the exact same problem with my 2001 Z71. It turned out to be the idler pulley for the ac belt. It was only like $30 bucks and like a hr to install and problem was solved
  3. TJbear

    TJbear Rockstar 100 Posts

    Its not that kind of noise. It is the compressor itself. It goes away totally when the system is off or the compressor cycles off.
  4. MightyMax

    MightyMax Rockstar 100 Posts

    '91 Chevy, V8
    I replaced my stuff on my A/C last year.
    I recently went out and put more freon in the system, but I think I put to much in.....
    The Compressor started making a Loud, but low grumbling sound....

    I put my gauges back on it to see the pressure (I didn't use them initially, dumb on my part).....
    And the pressure was reading higher than it should have been.
    So I let off some and that seems to have cleared things up.

    When A/C is on
    Low side should be between 40 - 45 psi (for mine)
    High Side will be between 150 - 200 psi

    So check the pressure. ;)
  5. vncj96

    vncj96 Epic Member 5+ Years 1000 Posts

    Clutch bearing in the compressor probably on its way out, you can buy kits to replace just the bearing or you would have to get a new compressor
  6. MightyMax

    MightyMax Rockstar 100 Posts

    If it is the bearing.
    I would go ahead and replace the whole unit (Compressor and Clutch).

    Just my opinion.
  7. TJbear

    TJbear Rockstar 100 Posts

    Thanks for the tips. I still have yet to check the pressures. Procrastination ftl. :lol:
  8. TJbear

    TJbear Rockstar 100 Posts

    Finally hooked the gauges up. Ambient temp around 80 degrees. Low humidity.

    Static pressure was 65/65

    At idle, max a/c, doors open: 43/225, vent outlet temp 48F.

    1500 rpm, max a/c, doors open: 33/200, vent outlet temp 38F............
  9. MightyMax

    MightyMax Rockstar 100 Posts

    Looks to me like your pressures are where they should be.

    So if the noise is bothering you, then I would look to possibly replaceing the compressor.

    If you do opt to go in the direction.....maybe before you do it.
    Evacuate the system and change out the orifice tube or expansion valve....
    As well as the rings
    You will want to do that anyways if you get a compressor.

    Go through and replace the various items of the a/c system that are the cheap ones.
  10. murdog94

    murdog94 Epic Member 5+ Years 5000 Posts

    Also if you do replace the compressor with a new one the only way they are going to allow you to retain the warranty for the new compressor is if you replace the accumulator as well. Just a heads up.

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