Hello, I have a 2015 Macbook Air. I7, 8GB Ram and 256 GB Flash. Now the fan makes this helicopter sound, when it is on It's "slowest", I could not hear the fan before when It was not boosted because of a demanding task. Now I hear it all the time in "silent" mode. I ran diagnostics, but It only said my battery was not optimal. Nothing about the fan. It worries me a little. My Macbook Pro toasted itself. Also It's very annoying. Anyone had this problem? I found a topic about the same issue from 2009. I can mis the computer for a repair in july ... Is the fan getting tired? Or could It just be dust.