Hi, my electric oven was making a racket and i took the back plate off and spun the fan, it was touching the heating element and I think the back plate, so i tweaked the fan blades and tapped the back plate out into a more concave shape, i think the girlfriend was hoping it would not work ( gets a new oven ) but it's lovely and quiet now and i wasn't even aware it was snagging the element to begin with.
Maybe the same with yours, maybe not, but worth a look.