Our outside AC unit sounds like a generator running

Call an AC company?

prayers sent

Good chance it’s the condenser fan motor - the bearings/bushings can go bad - often the noise is a high squealing pitch, at least it was when mine went bad.

Try this - pull the disconnect to the condenser, when with a screw driver, stick, branch, … try to spin the fan blade through the grill - if it only turns a 1/4 to 1/2 a complete revolution, as opposed to several complete revolutions, with a good, hard spin, then it’s likely bad bushings in the fan motor.

I ordered a OEM motor and replaced mine myself - I guess I saved a few hundred as a DYI. It was an easy job, but if you do this watch several Y/T videos of HVAC techs doing it first - the most common issue is removing the fan blade from the motor shaft, as they are often rusted on and there are several tricks the techs use to help remove them - fortunately I did not not encounter that problem. Secondly, the fan must the placed in the exact location on the new motor as the old motor - so you need to mark the location on the old motor shaft before removing the fan, and place it in the exact same location on the new motor shaft.

HVAC techs often carry a universal condenser fan motor on their trucks, which are fine, but they usually have an extra wire and the fan motor wire colors don’t match up with the original - that can be a bit confusing for a newbie to make all the right wiring connections, but one should not have that issue if you use an OEM replacement motor.



ETA: when the bushings heat up and expand you get the squealing noise, not at first, as you describe - same with mine.

Could be just your bearings. Some have oil ports. Worked for me a couple of times.

Truth be told, mine is kinda old so that makes sense

When I priced mine, the motors were about 300-400 and it's a DIY project if you are handy.

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Our outside AC unit sounds like a generator running

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if its the short rectangular green rheem then those fans are not generic and you need a specific type to fit it so its not something you should try replacing yourself. call a repair man and you can expect to pay about $300 total

I have the short rectangle rheem units. Had bad motor. Got info from motor and ordered from Grainger. Fan went right on new motor. $109.99