Pretty much needs replacing.
https/www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=Acer+Aspire+e5+575g+fan
how hard is it to replace?
I have replaced many. Just a bunch of screws. Could probably find a YouTube video of your make and model. something like Acer Aspire e5 575g disassembly.
I had a similar problem with my Acer Aspire E5 575. I replaced the fan, which is very easy task (compared to many other makes and models).
BUT the problem wasn't the actual fan. The problem was an inspection sticker that is glued into the chassis just right where the fan intake and motor is. This sticker then was loosened from other end and curled so that the end went into the fan and caused the grind noise.