Can't find the source of this whining sound

[YukonGold12]

Hey, there is a new sound my Yukon makes when it starts on cold days. It makes this whining sound when it starts and at times I can hear it around the 2k RPM mark when it's really cold and I am driving.

I have checked the pullys but neither seem to emit the whine when I place something like a screwdriver on them. It almost seems like it's coming internally. What should I check next?

 

[donjetman]

The ticking at the beginning sounded like lifter clatter.
Then I heard a dry bearing from a belt driven accessory (pulley, alternator, etc). Remove each belt one at a time.
Then there is a third sound, I don't know???

 

[ScottyBoy]

Definitely a bearing on one of the pulleys screaming. Its most likely the idler pulley or belt tensioner. But it could also be ANY belt driven pulley, so check them all.
If you have a Harbor Freight near you, go buy a "Mechanic's Stethoscope". They ate under 10 bucks and are super useful in situations like this where you are trying to pinpoint a noise.