MY AC cools just fine. But when it cuts off, the loud screeching sound outside can be heard from far away. This only happens when the AC goes off. There are no other weird sounds, any other time. The screech lasts about 2-3 seconds, as though the unit is winding down to stop. Please help.

  • I'm wondering if one (or more) of the bearings in your fan motor is going bad. While running it wouldn't make much noise, then during run it becomes hot. At the end of the cooling cycle, the fan would take about 2-3 seconds to spin down, which would account for the noise. You might keep an eye on it and see if the noise stops as the fan stops. – Pᴀᴜʟsᴛᴇʀ2 May 26 '15 at 23:12
  • Thank you, Paulster2. I will take a look and see what I can find out. I hate to get in there and start poking around -- especially since it's cooling so well. But that noise is so loud whenever it cuts off, that you can't ignore it. Believe me, I've tried! – Georgia May 27 '15 at 21:33
  • I think if you just observe (no poking needed) as it shuts down, it will become evident whether it's the fan or not. My money is on the fan, mainly because there are only two moving parts (to my knowledge) in the outside unit: the fan & the pump. If the pump was making the noise, it would probably be affecting the cooling. As long as the fan starts up and continues running during the cooling operation, it is logical it might be what is making the noise. – Pᴀᴜʟsᴛᴇʀ2 May 28 '15 at 10:34
  • First, follow Paulster2's advice. But if it's not the fan, it could be something weird with the valves or lines outside. Older A/C systems whistled quietly after the compressor shut off because the gas pressure equalizes. I've never heard of this turning into a loud sound, but I'm pretty sure it could happen if the right problem was introduced, like a pinched line or a reversing valve not moving correctly. – pbarranis Mar 14 '16 at 14:09

Your Answer


Browse other questions tagged or ask your own question.