Fan Noise

The climate control fan in my `99 Regal is making a "fluttering" noise when it's in the low speed mode. Has anyone here ever "tore into" the fan to try and fix this?

My girlfriend's '99 Olds Intrigue (similar car) did this too. I don't know what causes this noise. I tapped the bottom of the blower motor (no need to remove it) lightly with a hammer while it was running, and the noise went away. It's been over a month since I did this and it is still quiet. Weird huh?

Saturday morning I removed the fan/motor and I was able to disassemble the motor to the point where I could oil the bearings. The bearings are a powdered metal type and they soaked up the drops of 3-n-1 oil that I put on them. I then reassmbled the motor and put the fan/motor back in. It worked!