removing neff fan blade?

someone has already asked this but i have removed the nut on front of the blade which is left hand thread (anti clock to tighten) and removed the washer behind it but the blade won't budge at all, i've tried holding the thread with pliars and the blade won't move i don't want to go to mad or i'll ruin the threads and the nut won't go back on. any suggestions, what about heating the oven up first, metal contracts when it's cold does'nt it?(i have already changed the element but i can't get to the screw behind the blade.just 4 ref. the old element snapped off the said fixing when it was removed and the new element was installed by bending the top bracket out the way of the blade. it's the half circle element)