Any idea? 2008 Honda Fit w/ 115K miles

 

This only happens at initial start then goes away? We have something similar going on with our '07.

I'd spray water on the serpentine belt to see if that changes the sound. Does the noise vary with engine revs? You didn't try goosing it until the noise was gone, in the video.

 

the chirping sound is a glazed spot on the belt or roller

 

Because the belt system is so low to the ground I noticed mine gets wet quite easily and squeaks like that on occasion.

 

Sounds like the belt is either due for replacement (glazed/worn as doctor J hypothesized) or under-tensioned. Unless you've just replaced the belt and it's doing that, I'd say it's time for a new belt. You can confirm by doing the test Carbuff2 mentioned (spray a little bit of water onto the belt when it's doing that and see if the sound goes away).

 

Sometimes a shot of WD-40 on the Serpentine belt will season the surface and make it stop squealing, temporary fix but if the belt is getting dried out and such it helps.

 

Ugh... that took way longer then expected.

Idler Pulley & Belt Replacement

 

This is not a problem as long as problem is solved!

 

I had the same problem with the first tension pulley I bought. A different source had a better pulley (IMO).