Need help finding whining noise front of engine.

NP . Remember there are 3 of them so I would just remove the serpentine belt and spin each of them and whichever makes the noise just replace. Unless you want to do all 3 for preventative maintenance.

 

check all pulleys for side to side play, normally our idlers sound more like a crappy supercharger when going bad. That sound is 100% alternator failing. usually happens once the diodes start going is what ive heard. Easily way to check this wouldve been to reach down and just unplug the alternator while its running. Takes 5 seconds.