Whine from engine bay on idle/acceleration

Hello all.

have a 2005 pre runner v6 with 167,000 miles. When I start the truck I hear a higher pitched whine almost sounds like a belt or pulley but not sure coming from the engine bay. Upon acceleration the whine pitch seems to increase as I accelerate. The truck doesn’t seem any different driving and did a visual inspection and all belts and fluids and no check engine codes etc… anyone experience this and know how to remedy? What could it be?

 

What did it end up being? Mine just started today and what I'm reading might be the idler pulley....?

 

Mines does the same thing and has for the last 10k miles.
It sounds like a tiny supercharger lol

I'm just waiting until something totally breaks since I can't seem to chase down the culprit

 

It's either the serpentine belt or one of the pulleys. Spay a little water /lubricant on the belt first, then each pulley one at a time. When it quiets down, you have your answer.

 

Never a bad idea to change the idler pulley with the belt. At the least, give it a spin for loose/worn or tight bearings.

 

What he said. Been working to reduce whine since...horses.