2002 yukon whine when cold outside

[TAHoe2213]

Can anyone help me out i have a 2002 yukon 5.3 that when it is really cold below 20 i get a loud high pitched whine at idle and while driving it goes in and out almost like a bad bearing maybe ?. if i pull into a garage within five mins of warming up it stops so it is kind of hard to find. I have changed out the alternator, belts, the three belt tensioners, the power steering pump is new i have no idea. And my mechanic has a hard time trouble shooting it because of it going away when you pull it into a garage with heat. Any help would be great.

I have same thing going on with my 04 when it was -20 in chicago last week or so it was the worst yet.If you find out what it is please let me know Thank you

 

[Doubeleive]

100% of the time it has been the a/c tensioner for me, easy $30 5 minute fix

 

[CFD Jerry]

Here is an update, but not cold enough to do it yet... I did have to change the power steering pump due to it going bad just a couple months ago and went with full synthetic fluid. Then I notice my alternator had a squeal when I was cleaning under the hood this summer and recently noticed it was getting pretty loud.

I can tell by the new verses old it is spinning much better so I would assume bearings were going. Where in summer with heat metal expands and in cold it contracts.

So we shall see when the temps drop to super cold what happens....