no the fan should rotate freely.remove the rear panel from inside the oven to expose the fan/motor,check that the fan motor is well secured to its mounting plate.spin the fan using your finger to see if the fan is spinning off center, or feel for any side, or up and down movement,.may need to replace either motor or fan,or possibly both.remember to isolate the power to the appliance before you start your investigation.
mech monster, November 2011
