Hello, I'm a new member looking for some help on my 2011 135i N55. Hopefully I'm posting this in the right section.
I have only had it for about 9 months now and it recently started making this squeaking/chirping noise. It started out as a slight chirping, as you can hear in the first video, but now a week later it's louder and more frequent, see second video. It's heard at idle and revving up to about 4k rpm. The squeaks don't change much when I rev it. I don't ever hear it when driving though, possibly because of wind or road noise. So far I haven't heard it after cold startup. It usually gets bad after driving it for a bit, like after my 30 min commute to work. I figured it was just a belt issue, but after searching I've seen that it could be multiple things, so now I'm even more confused.
I sent the first video to a trusted mechanic and he says it's probably a bearing going out somewhere: alternator bearing, idler bearing/pulley or the tensioner itself. I haven't taken it up there for him to check it out yet because I want to get a better idea of what it might be first.
What do you guys think?
First video:
https://photos.app.goo.gl/pdk3x6W74rHkkGr93
Second video, a week later:
https://photos.app.goo.gl/X7m1RQ6N2ronxUpf2
Any help would be appreciated.
Thanks.