The engine is a 5.7l hemi. I have been chasing a noise from December on. It is not a daily driver. I have a stethoscope and used it to try to pin point the noise. It would go away when the engine is hot, but increased and decreased with rpm's. It is difficult. I started with changing the belt. That made it go away for a week, then it came back. Then I herd it from the idler pulley. I replaced that and its still there. I thought to have narrowed it down to the fan clutch. I thought it was the fan clutch and went ahead and did the clutch delete along with installing an electric fan. I have had a buddy come up with his and help me out. We crawled under and on top listening to each pully. He said he herd it from the powersteering pump. I listen to where he was listening and could hear it somewhat. I replaced the power steering pump. The noise then became a constant from here on out. I listened again and could hear it more from the alternator. Thinking a bearing has gone bad, I replaced the alternator. Now the noise is still there, but goes away when the engine gets warm. These are the parts I have replaced in this order.
-Idler pully
-power steering (pump)
-belt tensioner
-Alternator (today)
I have pulled the idler pulley off and lubed the bold and seat it sits on (no change in noise). All that's left is the coolant pump and a/c compressor and I am 99% sure its not the compressor. Please watch and listen to the video. Thank you guys in advance.

 

Have you tried running the engine for a short time without a belt to see if the noise is still present? I would suggest trying that if not. That will at least determine if it's something that's belt-driven or something internal to the engine.

-Rod

 

I would remove the fan belt and let it run Like the other post had mention. Yes I have seen water pumps make that type of sound.