The bearing is lubricated with grease and should have a metal shield (non contact), adding oil to it isn't ideal but it could help buy some time. If the bearing has a rubber seal, which it shouldn't since it is an electrical motor application then trying to add oil pretty much is useless since that seal is more than likely going to be a contact seal which keeps containments from getting in (meaning that oil won't be reaching the balls either).
So in short if the noise is coming from the bearing, replace the bearing.
Carlyle, IL
