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Is it a dangerous condition if the compressor makes this squealing noise? I left my home for two weeks and when I came back my condenser fan motor wasn't working. So my compressor was running non-stop (I had thermostat low) without the temperature being exhausted by the fan motor. Afterwards, I noticed the squeal. Could it be caused by being run so hard?

Its has a heat pump as well.

  • Condenser Model: Goodman CPLJ42-1
  • Compressor Model: Genuine OEM Part # CR35K6EPFV875

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I wouldn't say it's dangerous unless you live in Death Valley. It's just not long for this world. Every time you hear it squeal remind yourself you'll be spending $1k on a new condenser soon. Or you might get lucky and it's just annoying for the next 20y.

It probably starved for oil and scored itself. With a new fan up and running everything should be back to where it should be, provided there aren't a bunch of shavings clogging the orifice.

When you have the unit replaced ask them to flush the lines.

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  • Thanks! That was very helpful. When you say lines, what do you mean? The freon lines is the source of the squeal or something? And where is the orifice? Sorry, I don't know some of these things so I am bit curious.
    – LeanMan
    Nov 20, 2021 at 5:58
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    The "sealed unit" (the, not-serviceable, compressor) is what squeals. The Freon lines have oil in them from the compressor which gets pumped around in a circle, which now has at least some amount of metal shavings in it. The orifice is inside the nut you can see on the "high side" (the small tube) right where it connects to the inside unit (don't ever touch that) or if it has a TXV (thermostatic expansion valve) it's a weird spider looking thing just inside "the coil" (the thing on top of the furnace; the other half of a split system's compressor).
    – Mazura
    Nov 20, 2021 at 6:17
  • If it's getting swapped to a new type of refrigerant, flushing the line sets may be mandatory; some oils aren't compatible and manufacturers change what kind of oil they use in the eternal search for a better SEER (Seasonal Energy Efficiency Ratio).
    – Mazura
    Nov 20, 2021 at 6:17
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    @LeanMan - a low side hot to the touch means the compressor's running but its fan isn't. Scoring of its impeller is from the oil not returning because the system can't push the high side any harder because it's too hot. Pressure (and so the oil) is back to where it should be so now it just squeals, except that means friction is still having its way with it. Could die today, or....
    – Mazura
    Dec 10, 2021 at 8:45
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    You have to do a cost, benefit, risk analysis. Of when you can afford to do it. When if/or, it's unacceptable to be w/o for a week if it fails (Death Valley). The intrinsic danger is only to itself burning out totally.
    – Mazura
    Dec 10, 2021 at 8:49
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The other answer assumes the compressor itself is failing and this could be a cause of squealing. Without hearing it, I'm writing this based on

my condenser fan motor wasn't working.

I have had this happen during heavy summer use, the fan motor siezes up and squeals or doesn't turn at all. I was able to push the blade and get it started for a couple times, but eventually the fan wouldn't really turn at all.

When this happens, it's due to either the bearings or shaft waterproofing seals in the fan motor itself wearing out, or the run capacitor (metal cylinder about as big as a regular Red Bull can) can die and fail to start the motor properly (usually seen if it runs OK after manually pushing the fan blade). Run capacitors are cheap ($25-30 in my area), but electrically somewhat dangerous. Fan motors are not (~$250).

As of this writing it sounds like you've already replaced the fan motor and that worked for you. For anyone else stumbling across this Q&A later, the process to replace the fan is pretty simple:

  • Write down or take a photo of the label on the fan and the run capacitor.
  • Get replacements from an HVAC supply house.
  • Take a photo of the wiring before you take the wires off the fan and capacitor.
  • Shut the AC breaker off.
  • Replace both (it's debatable whether this is necessary, but run capacitor is cheap and the old one might not drive a new motor well, burning both out again). Discharge the capacitor before handling it.
  • Make sure all the wires are routed out of the path of the fan before reassembling.
  • Turn breaker back on and test the AC function.

I had another step in my case, where I had to run a window AC unit temporarily because of a pregnant wife in the house at the end of July while I was learning how to do this, but that's another story...

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  • The squealing definitely happens with or without the fan motor running. We had the run line of the fan motor disconnected during diagnostics and the squeal still happened. I'm guessing, it makes sense that if the compressor wasn't well lubricated after being run so hard that the inside had a pretty hard time while the fan wasn't helping it cool down. Even the fact that this means that the suction line was hot to the touch is bad considering this means compressor had nothing to keep it cool... ::huge facepalm::
    – LeanMan
    Dec 10, 2021 at 16:32

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