I have a 2000 Blazer V6 that has growling bearings when first started on cold mornings. How do I identify which pulley has bearings going bad? I took the belt off and spun by hand the alternator, idler, and tension pulleys. None seemed too bad.

Thanks for any advice,
dbteeitup

Try carefully using a mechanic's stethoscope or large handle screwdriver. The links below may help:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-5.html#post578394

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-6.html#post637296

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-6.html#post666293

With the belt (tension) removed, it's unlikely you'll be able to tell that a bearing is bad--it would have to be really bad.

Wait until its squealing again, get a long screwdriver and put it up against the pulley shaft housing or brackets one at a time while putting your ear to the screwdriver. You should be able to hear the squeal through the driver loud and clear, just be carful when doing the lower pulleys as you don't want your face to get chopped by a fan/belt.
This is my method, hope it helps