Belt or belt tensioner. Cam belt is toothed and would not make that sound when slipping. If the cam belt is due to be changed according to the mileage or time shown in the maintenance manual, do it. Don’t push your luck.
Maybe its just excited, my 1 year old nephew does that too.
sounds like a belt is rubbing definitley check the belts for fraying, they might also be slipping from wear,
Could be the alternater. Same thing happened in my car got to the point it got lou then it just stopped whining was the alternater going.
my guess is the serpentine belt. I had the same problem with my 99 deville. Was real bad after wet weather too then became constant noise no matter the weather. Last month i changed the serp belt and its gone!