Name that noise.
 

My zero mile Texas Speed 570 horse LS3. The belt was taken off and cleaned with Dawn. All the pulleys and idlers were cleaned with alcohol and Dawn as well. The sound persists! I used a screw driver and my ear in an attempt to isolate it, but I can't. Everything turns freely by hand with no noise/grinding. Thoughts?

https://www.youtube.com/watch?v=aGTQVrdE-3g

Did you put oil in the engine? Just kidding!
Sounds like a bearing to me, maybe alternator? Tough to diagnose, even with video...

yeah i would agree with scott, on a different note i had a old vacuum line go for a s**t on my chevelle quite some time ago and it created the most annoying weird squeeling flutering humming noise , had the dealership mechanics in fits trying to find it then when we did no one could believe it almost like it was coming apart from the inside . if you can try to get a piece of a hose or a stethoscope ,would work better then a screwdriver

It does sound like a strange vacuum leak.

Did you take the belt off and run it to see if that was the noise?

Forgot to mention that! I ran it to verify that the noise was there at idle and higher rpm. I then pulled the belt and ran the motor to verify that the noise was gone...and it was.

try a new belt ?

Idler or tensioner bearing is bad....IMO


T,

^^^^^^^^^^^^^ This!

Check your belt alignment to see its its misaligned. Make sure the power steering pulley is all the way on too.

I did have to change out my power steering pulley for another that game me more clearance at the upper A-arm. I also had to use an elongated pressure hose adapter to get clearance for the pressure line A/N fitting. I laid a straight edge across the balancer and compared it to the PS pulley...the pulley needs to slide on a little over 1/16" to match the balancer.

That will cause that noise on a surp belt setup.

Well, I pushed the PS pulley on as far as I could go with out hitting the pressure line fitting. The alignment with the balancer isn't exactly perfect, but as close as I can get it with my combination of parts. I started the motor up and got it up to around 140 degrees with no noise at idle or when reeved up. Hopefully it stays away!

Good for you! Simple fix is always good!

I ran into a noise problem like this on my LS swap. I am using Fbody accessories. After the engine was warm I had belt noise. I replaced the idler, the tensioner and a new belt from NAPA. Thought it might be a bearing in the alternator but I had it checked and it was fine. The guy that checked the alternator said get a different brand belt. I went to Oreilly's and I think purchased a Goodyear belt and no more noise. Been great for two years now.

I ran the car up to operating temp the other day and I can still hear a little chirping at idle, but nearly nothing when the motor is reeved.:bang:

Goodyear Gatorback belts are the best for removing noise. I have one on my 67, that had chirping issues. I was running a Gates previously. Also ran a Gatorback on my C6 vette with an A&A S/C.