My 98 Legacy has a constant ringing noise coming from the engine, which becomes louder as the RPMs rise. I've attached a video of the noise at idle; I suspect it is from the pulleys, but I'd like a second opinion.

 

is the video.

Edited July 29, 201510 yr by nithinmike

take off both accessory belts and start the engine again.  hopefully the noise goes away meaning it's one of those pulleys like you suspect.  if there's still noise it's likely a timing belt idler going bad and needs to be addressed immediately.

Suspect it is a bad bearing in a pulley, likely driven by a fan belt. If you are fortunate, it is the alternator, which is not difficult to replace. Remove one belt at a time to see if that stops the noise, to help you identify which pulley. If not there, then one of the pulleys, or tensioners associated with the timing belt. It is something you need to fix right away, before the bearing fails completely "locking up" the pulley.