Hi Mike, a lot of times the fans will make a lot of noise because of imbalance caused by accumulated dust. Have you tried vacuuming out the fan, and even using a brush or Q' tip to clean off the blades?
If the fan motor is squeeling, have you lubricated the motor?? The designs vary, but most have a small hole in the 'hump' in the cover over the bearing so you can get a drop or two of oil on the bearings.
Hope this helps.. Greg L