Hi everyone!

I'm having a problem diagnosing this noise, coming from somewhere in the serpentine belt area... Belts have been changed, AC compressor rebuilt.

Noise is always there. When cold, when hot, lower revs, medium revs, only at higher revs you cannot hear it anymore but I think that's due to engine noise overall.

Here's a video...


How do I diagnose where this noise is coming from?

 

take serpentine belt off and turn on car...if noise goes away then you know it has to do with that...ac, alternator, idler pulley, etc...if noise goes away try spinning one by one and checking them out...

 

I would take it off and start the car again . If noise is gone it's either tensioner or one of the pulleys .

 

I took the belt off, started the car and no more noises.
Replaced the belt with a new one and it seems to run fine now.

Lets see what happens after 10-14 days because the belt I replaced was only a few weeks old.

I also looked at the pulleys and they all seemed fine except the alternator pulley has a little play on the outer edge. Could that be the problem, that the alternator pulley slowly damages the belt and after some time this sound reappears?

Well, we'll see...

 

could be...maybe when you installed the new belt you tightened it more and stopped the noise for now? Def need to check out the alternator play...