[HayZee518]

Boy, have you got lazy tech people. Seems that they are quick to suggest ways of doing things but lack the get up and go to actually do the work. Crud on any fan will make it out of balance and reduce its efficiency to blow air. the extra weight on the fan will reduce the life of the motor bearing on the end its fastened to. just a guess but the allen screw in the fan hub may be a 1/4-20 or a 5/16-18 thread. a 1/4-20 is probably a 1/8th inch allen. 5/16 is 3/16" allen. use plenty of a penetrating oil and gently tap the hub. then try to loosen it.