Where could sound come from? Montana 2004

[simoon]

Hi,
I want to ask if anyone has solved the same problem here.
The engine belt is OK and tightened. But I can't figure out where this sound comes from (recorded in the link video).

video link on YouTube.

 

[melsg5]

Use a length of rubber hose to act as a stethoscope to find the source

 

[thundercat]

Some time I has have similar sound, belt and tensioner discarded. It was fixed by cleaning grease and dirt on the pulleys through towel paper pieces and brake cleaner. Try, first remove serpentine