Hissing Sound from under car
 

Hi guys,

Could you tell me what the 'hissing' sound is in the below link. It's coming from under the car.

Thanks.

https://www.youtube.com/watch?v=CQMqLDocGrs

Really hard to tell anything with that recording but hissing sound could be an exhaust leak in combination with a blocked cat or a vacuum leak, maybe even at the pan gasket since the crankcase is under vacuum and looks like you some oil leaks. Maybe try tracing sound with a piece of rubber hose held to your ear.

Maybe a bad idler bearing, alternator bearing, etc?

Seems to change pitch a bit like bad bearings.

Hissing Sound from under car
 

It sounds also like metal sliding on metal (like a dragging brake shoe). The ac clutch can make that sound. If the ac was turning on and off that would make sense. The sound seemed to be coming and going, if that is accurate it won't be most of those suggestions above.*

Any of the rolling accessories could be generating the sound, so were it me: have somebody turn AC on/off see if the sound changes, if inconclusive, take the serp belt off and see if the sound goes away then you can least discount all the spinning stuff.

You said the sound came out the bottom but the hood was closed??

* Crowz replied while I was typing. That "above" suggestion is the same as mine.