i have a bryant cooling system for my home that is approximatly 7-8 years old. prior to using it for the first time this year i took the panel off the side and cleaned out all the debris from last season. there wasnt that much. when i turned it on for the first time it worked fine...it cooled down out since so it has been shut off for about 2 weeks...its getting hot again so i fired it back up the other day....it got cold in the house but it seems like the big fan on top of the unit is making a whomp whomp whomp whomp sound to the point that it was rattling the china on the wall that is on the other side of it...i again cleaned it out found a little debris in there but hardly any and most of it was on the bottom of the unit under what i think is the condenser as it is wrapped in a foam type blanket...i sprayed wd-40 on the fan shaft under the blade and on top of the blade just before it goes into the fan motor. the sound is still there but not nearly as loud as it was before. it is not shaking the china any longer....is this something that i should worry about and get fi looked at by a professional right away or maybe let the wd-40 work its magic for a few days and re-evaluate it then...there are some signs of rust on the fan motor shaft but barely any....thanks for any help i receive!