"W. eWatson" wrote:

It' got into the 90s today here, and I decided to turn on my Whirlpool a/c,
model acq062mm, and enjoy it in one room. It was doing fine pushing out cold
air, but the fan kept getting louder. The sound is definitely connected to
the rotation of the fan. I finally stopped it and looked for the owner's
manual. It was really of no use. Any ideas? It was working quite well at the
end of last summer. Since a foot or more hangs out the window, maybe
something got into the fan area.

While all the others are possibilities- I'll go with Occam's Razor.
If you can get air, or a powerful stream of water back to it, try
cleaning the fan blades. The last few window bangers I've bought are
designed to keep a puddle in the AC that the fan dips into. Great
place for mold to grow, attach to the fan & throw it off balance.

You could narrow the possibilities, perhaps, by trying to describe the
noise. Is it fan noise, bearing noise, a bang on start-up, or a
rattling sound?

Jim