Hi Guys, I realise this is an old thread but I recently tried to do this on my oven and failed miserably which is how I found myself here. I removed the central nut (left hand thread) but couldn't remove the central washer and didn't come close to budging the fan and I have to say, I was reluctant to use molegrips on the thread of the central spindle or squirt WD40 into the oven. I did try one or two light taps of a hammer but very quickly realised I was wasting my time. That said, there is a method which works and works well - forget all the foregoing pieces of advice and do this . . . . .
Turn your oven on to max temperature but without the fan running. I figured that a static fan would aid temperature buildup in the fan itself and besides, I had already removed the central nut at this stage. Now once up to temp, leave the oven for about 15 minutes or so before turning it off and switching off the electric at the wall.
AT THIS POINT, YOU NEED TO BE CAREFUL!!! If you aren't extremely careful, you are going to burn yourself and so take great care. Wear long sleeves and some heavy duty oven/fire gloves and simply open the oven door, reach in and grab the fan blades with from both sides - hold the vanes, one in each hand from opposite sides and a single sharp tug and the fan will come flying off - no problem whatsoever. This will work because the oven heat softens up the residues sticking the fan in place but moreso because with heating, aluminium expands at twice the rate of steel and the fan is simply much looser on its spindle. Believe me, it works. Just put away the WD40, the molegrips and the hammers - you won't need them - nor will you need to drill a hole in the backplate of your fan. Try this method first and don't waste your time trying anything else - just learn from MY mistakes!!!!!! :-)
Alan G
January 2020