I’m having a problem with the fan starting up. A few days ago it wouldn’t work at all. I put it on today and it would not come on but after about 30 seconds it slowly came on and has been running strong for about an hour. Freezing has not been an issue. Would it be beneficial to take it out of the casement and clean it out?
It would not hurt to open it up and clean the fan.
If you can put a drop or two of oil on the fan bearings.
Use a good quality oil (sewing machine or 3 in 1). I would not use WD40 as it will not last very long.
You may have to replace the fan.