The noise is horrendous as this is metal on metal. Looking at the blades I can see where they have worn down. This seems to be due to the spindle being misaligned. The easy thing would be to replace the whole motor/fan assembly but I believe it is obsolete. Since it is an alignment issue ( if I slide the fan to the side and hold the oven at an angle the noise does not occur!) I wondered if there was anything I could do to keep this going.