Sort of a “wooing” sound that’s in sync with the RPM of the engine.

I’m hearing a “wooing” tone that goes up and down with the RPM of the engine. It’s become louder in the last 20 miles. It’s way too loud to be a typical 4Runner sound. It doesn’t sound like it is internal to the engine but rather something that’s spun by the serpentine belt. Any ideas?

 

Normal sound. Sound like a supercharger?
I’ve had two 5th gens and they both make the noise, along with plenty of others on here.

 

Yep both mine made it too, it's normal. It does sound like a supercharger kinda, I'll agree with you on that.

 

It is possible a failed bearing in a pulley. Had it happen on my Tacoma, it was insanely loud. Used a mechanics stethoscope to identify the engine pulley and swap it.

 

Is that you Rick Flair?

 

https://www.youtube.com/watch?v=_0t6llGkBLo

 

@Rich4x4 would it be possible to get a video?

If you're concerned, might as well take it to the dealer and have them look at it.