My screeching accessory drive noise finally got bad enough that I thought the dealer would diagnose it.
Of course a year ago I asked then to loosen the serpentine belt and spin the idler pulley to see if one of the bearings was going bad.... But noooo, they couldn't find a problem and I doubt they did what I asked them to do...
I took it in today, it screeched about 10 minutes in to the drive instead of the usual 15-20 minutes, but of course idling on the service drive waiting for a service writer, it decided not to make noise when they got to me.
But low and behold they re-created the problem. And the diagnosis: an idler pulley bearing was going bad!
Looking forward to having both a silent shifter (fixed that myself) and a quiet accessory drive for the first time ever.
Hmm, they passed the car on to another tech (one that knows more than replacing parts) as the pulley and new belt didn't fix the problem. They are looking at the engine. Ruh-roh... I don't want to think about it.