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Automotive AC Question

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  • Automotive AC Question

    The belt on my air conditioner was broken due to a locked up tensioner. Before I replace the tensioner and the belt I wanted to ask someone who knows more than me a couple of questions. With the belt removed the clutch spins freely and the head or actual Electromagnet portion of the compressor spins with a decent amount of tension but I can turn it by hand. If the car is running and the AC is turned on without the belt in place, should both the clutch and the other piece spin freely or should there be tension ?
    I hope my question makes sense. I just want to get some opinions before I invest the money in a new tensioner and belt just to find out there’s still something wrong with the compressor itself.

  • #2
    The pulley should spin free the center plate will have some resistance, that turns the compressor crankshaft. it will always have some load.


    • #3
      Yes. Bob, this (unsaid) is a cycling clutch so compressor is an acting pulley only and engaged a pump. Trouble is tossing a belt or 'THE' belt renders you a pedestrian A/C or not,
      MetroWest, Boston


      • #4
        Originally posted by BobOMcA
        If the car is running and the AC is turned on without the belt in place, should both the clutch and the other piece spin freely or should there be tension ?
        As you stated: if engine is on, and AC switched on, the pulley should NOT spin freely. The compressor should spin with a decent amount of tension if one tries to turn it manually - but know that doing that "test" is QUITE DANGEROUS TO YOU, AND NOT RECOMMENDED. Stay safe.


        • #5
          BobO: What is this thing? Most or all tensioners that come with pulley should have an index mark and timing covers another. New belt and tensioner want it towards mark for "how much it will go and work, it wears to the other has to go appearance doesn't count at all if wrong.
          Testing with key or car to run watch out just watch.

          Assorted stuff out there runs compressor if engine is running when it feels like it or electric fan(s) on. Depends on what this is and model year IDK if that info is clearly listed for each model of everything,
          MetroWest, Boston


          • #6
            Thank you all for your input and tips. I ended up replacing the tensioner and belt only to discover that the system was also low on charge, but the compressor is ok. I was able to recharge the system and it is now working. I also did some basic leak testing but so far I haven’t found it yet. This system is on a 2006 Chevy Tahoe with rear heat and air. Hope to locate the leak or hope it’s a slow leak since I believe Chevrolet uses the AC compressor in defrost mode. Thanks again everyone.


            • bmills2@twc.com
              [email protected] commented
              Editing a comment
              Tahoe leaks at the high pressure valve , also the lines over the rear wheel where rubber covers a/c line gets pin holes under rubber covering. caused by salt.

          • #7
            Yes A/C, compressor can engage normally for defrost and other modes that include it.

            Just leaks: If it's right now or end up boosting it really learn it. Too much is the worry. Some or many of these put compressor low IDK subject more to choking on liquid.

            So see if there's dye in it now just smear some dirt from low port and cap must be OE grade for GMs + others. UV light or some the color will just show. Oily areas seen on condensers dirty or run fingers low on anything, connections/gasketed items same deal.

            My fav is still a sniffer with no wind outdoors new/reman or just test behind clutch. If using one practice settings with even carb cleaner or something for it's sensitivity.

            Dreaded would be if it goes off inside at a vent with blower and A/C just shut down. Can also be a drip hose for the water a Q-tip if oily.

            Leaks are sometimes so slow and hidden this era learn boosting, touch and feel plus pressures, temps everywhere live takes remotes or a helper to read actual temp not just forecast or guesses. I won't expound it's only possible on higher capacity systems otherwise a high risk err not to if so.

            Glad it works and luck with leak finding if not obvious,
            MetroWest, Boston


            • #8
              ? Comment just made on this? 2006 Chevy Tahoe.
              Cycling issue bmills said rusted lines over rear wheels?

              I'm not sure if it has rear air thought these were mid-ship ceiling lines would run under then up not near rear wheels TMK.

              This is an old thread hope it's solved by now inserting comments from 6 weeks ago is confusing dual air not mentioned?
              MetroWest, Boston