Not a noisy motor problem, but three days ago I decided to wash down the condenser coil. I turned off the power at the disconnect box first like you're supposed to do. Washed all the dust and debris out, flipped the switch back ON and ... No compressor function.. dead! Uh oh! All sorts of thoughts racing through my mind, like a $2,000 condenser-compressor replacement! What the heck did I do?! Gathered my thoughts, checked the breakers in the electrical box in the house (all OK) then got out my meter removed the side electrical panel from the condenser unit and started checking power. One side of the AC was dead. Went back to the disconnect box, had 238V coming in. Turned off the power at the breaker box and checked continuity of the double-pole disconnect switch. One side was open. A failed switch! Went to Home Depot bought a new disconnect box for $15 installed it and now all OK! Phew! Had me going for a while!
I've had a noisy fan motor too several years ago. It was loose and rattling in the worn out bearings. Bought a replacement on Amazon. Installed it, nice and quiet.