Check run capacitor for condenser fan, if it is domed on top or swollen that may be the problem. Went on a call 3 ton Goodman condenser fan was turning backwards, drawing air in through top, cooled ok until the heat of the day. Capacitor was bad unit ran for 2 years like that before the guy would ask for help.
The condenser fan is outside correct? If I put my hand over the top of the unit, air is being pushed out. Would I not feel air if it was going backwards? I did look at the capacitor, it 'looked' fine. I did notice that the contact panel had some black residue on it.