Foam cleaner on the fan blade is fine although most of the time foam is used to clean the condenser and evaporator coils. It won't hurt anything to leave the unit running. Just make sure none of it gets on the electronics. You can also spray it with a little water because the fan motor is sealed. I've always used an air compressor to clean areas not easily reached with foam and water. What sort of environment was it used in where the fan blades managed to get this dirty in a year?

Its just been in my NYC apartment window. Today I removed it and removed the case. The fan was not very dirty. It was the blower wheel that had mold all over it, and I had mistaken that for the fan (couldn't really tell what I was looking at until I took it out of the window).

I cleaned the wheel and fan and it is still making the noise. It definitely sounds like it's coming from the fan area. I've wondered if it's bearings making the noise. Although the fan rotates just fine by hand and there is no resistance at all felt.

I have read that sometimes they have oil ports, but I am unsure if mine does, and unsure how to disconnect the wiring to remove the fan assembly to look for it.

I wrote down some info from the fan motor and it's Welling YSK70-4AF and also saw YSLA-70-6020. I think one of those might be the model number? Lol. Is there anyway to find out if they even have oil ports before I mess with it?

Is there anything else that can cause a sort of grinding and wind tunnel noise besides the fan motor? I know it's not normal because it ran quiet last year, and my other identical unit still runs quiet.

Any suggestions is much appreciated.

Thanks

A bunch of people have complained on Amazon about weird noises coming from the fan in the 6000 btu Frigidaire AC's. I recall one guy saying it was so annoying that he removed the cover and found something rubbing against the styrofoam inner wall. It's definitely possible considering how light weight window units are made these days and easily could be knocked out of "square" with some rough handling..

Thanks brice I will check for that.

I had a clicking noise happen on small unit some years ago. Not positive but it may have been a 6K BTU Friedrich bought in 1984. Anyway, upon investigating I found a shard of the styrofoam insulation lining the blower wheel compartment was protruding and rubbing on back of the blower. Simple enough matter to poke down in there with a screwdriver or knife blade or whatever it was I used and rub the shard clear.