You could have a few things, one could be the bolt holding the fan on is loose, another the bearing that the fan bolts to is bad . I would ck the bolt and then take a large screwdriver and go between the pulley on the back of the clutch and the housing for the bearing (metal thing right behind it) and gently see if it will move alot. Be sure to ck and make sure the fan isnt hitting the shroud also.
