For at least a year and a half now but probably longer, my PS3 Slim 120GB (purchased late 2011) has been making this loud screeching noise every now and then. I don't know if it's the HDD or the bluray making it, though I'm guessing the hard drive. It's been more frequent lately.
The noise mostly starts when the console has been idling for a while or when I leave Netflix paused, never when playing games.
There are slight variations in the duration and frequency, sometimes it won't make any noise at all for several hours or days. I haven't notice any change in performance or errors when using the PS3.
Been looking around the internet for answers or people who have the same problem but found nothing so far. Except for this being annoying and scaring the shit out of me at times (it's loud) I'm worried that one day the console will suddenly fail and I'll lose all my games and stuff.
I managed to catch it today by leaving my phone recording on top of the console for ten minutes. Here's a link to it: https://www.dropbox.com/s/l5im4uvt88n4jxm/Record_0074.mp3?dl=0
Hopefully you guys can identify it for me and let me know what to do!