Squeal sound coming from UNDER the truck

Long time lurker, first time poster, but for a while i have had this sort of squeal sound coming from under the truck and near the passenger side. I noticed it awhile back at a drive through window but it didn't bother me that much. Couple months later, its starting to annoy the crap out of me because i hear it every time i am idling and near a wall. It seems to only do it when its warmed up. The sound is more noticeable when the A/C is on as well. I have crawled under and the sound seems to be coming near the cat and around the manifold. I've included videos that showcase the noise and where i believe its coming from. If someone knows what this is and there is a thread already created please provide a link as i have yet to find someone who has the same sound and general location of said sound. 2012 prerunner 4cyl with 70,000 miles.
http://youtu.be/emRY8InMY_o
Could it be as simple as the spring loaded bolts need tightening?

 

Sounds like the serpentine drive belt to me.

https://www.youtube.com/watch?v=KG3qwjiCWQE

 

Or the power steering pump might be low on fluid

 

Sounds like a bearing to me.

 

You will have too get under the truck when its running too trace the problem.

 

Just replaced the belt a couple hours ago and there was no change in sound

Its possible, i did spin one and it had some slight resistance to where it would only spin a second or 2 after spinning it

It was running in the video and the sound seemed to originate from that location i just couldn't pin point it due to other noises.

Ill check it

 

Checked it and its 3/4 the way to hot which seems right since i just got finished test driving to see if the sound went away after a new belt about 1-2 hours ago

 

1 idler pulley spins more freely than the other 2 but there is no sound and all of them have the same amount of wiggle

 

http://www.youtube.com/watch?v=LOgZfXQfHso&feature=youtu.be
Heres a better version where you can clearly hear the squeal.

 

Idler bearing or belt tensioner pulley it sounds like

 

^^^

 

Revisiting the problem, i got bored and dropped the skid plate to get a better look at the tensioner pulley while it was running. http://www.youtube.com/watch?v=VBtatMHpcrw Could this make the noise i am experiencing. Generally i would associate a bad bearing to be a more of a metal grinding on metal sound and not a high pitch whistle/squeaking sound. I read somewhere you can just take off the pulley on the tensioner and not replace the whole thing. Would a

$40 Gates 36173 DriveAlign Belt Drive Idler/Tensioner Pulley

Gates 36173 work?

 

My hearing must be worse than I thought. I don’t hear anything unusual in all the videos.

 

@Pr3runnerTaco take the belt off and try to "wobble" the idler pulley like you were testing for a bad wheel bearing (push/pull top and bottom). If there is ANY play in it then it is probably bad. If you've gone through deep water recently that could be why (it was for me). The bearing shouldn't really make any noise and should have a good resistance to spinning since it's packed with grease. I have a bad one in the garage if you're interested to hear what it sounds like.

To be honest, kinda sounds like a tiny exhaust leak in the first vid.

 

You auto or stick? If standard, push clutch in and see if it goes away. If it does, throw out bearing.

Auto, take belt off and start it. Just for a sec. Goes away, you know it's in there.

 

I have made a discovery just now. I parked with the passenger side near a wall and pressed in the emergency brake and slowly revved it to 1500 while in D and the whistle grew louder as RPM increased, any higher and the engine noise took over.

Its an auto

 

Ive had the same sound for months. Only comes on in the morning when the truck is cold and just starts up. I believe its a bad bearing/pulley. Its definitely coming from the belt area

I also had another loud high pitched squeak as well when driving/idling which turned out to be an extremely small exhaust leak at one of the flanges past the CAT. It would only happen at super random moments like idling at a stop light, then would go away entirely when I took off, only to return again at like 45km/h then go away again 5 seconds later.

 

ill look around there in the morning and see if i can see anything

 

I only figured out it was my exhaust because I tried all other options. I tightened down a few bolts on my exhaust that came loose and it went away.

 

Bolts on the exhaust that i could get to are tight to the point i couldn't turn them and didn't see any pin holes on the pipe and from what i could see the headers looked ok. To add to the list ive noticed that when the compressor kicks on the sound either starts or is amplified to the point i can hear it. Just to add that to the list of possibilities.