Furnace blower

[RonS]

Our furnace is heating and working great in this cold weather here in El Paso. However our blower fan is getting louder each day. Does not sound like bearings or anything striking the fan blades. So I dont have a clue of what to do about the sound. Am I to do some maint on anything?? I have done nothing to the furnace since new. Any ideas about the sound, and should I be concerned???????
Thanks Ron

[hitchup]

Manual says they need to be cleaned of debris during annual maintanence. Remove vent panels from the exterior and vacuum out. You might have something living in your furnace. We had mud wasps trying to build a nest in our Elite.