I can't quite describe this sound but I will try anyway, maybe someone can tell me what it is.

I've recently just started noticing this noise. At first I thought it was my cone intake. But if its that then the sound should be more noticeable from the driverside of the engine bay. However, this sound is more noticeable from the passenger side. The sound is very similar to the sound the cone intake makes at idle. My friend describes it as a sound coming from a Ducati bike when the clutch is disengaged. Does anyone know what this could be?

 

I have the same problem, seemed to be the pulley, but im not too sure, havent figured out exactly what it is also.

 

Yeah I was thinking........I'll just wait til something breaks but that just doesn't sit right with me. Someone told me it could be the alternator or water pump. The water pump makes this bearing sound when its about to go plus coolant should drip out of the water pump if its about to fail. The alternator makes a knocking sound when its about to fail. So I don't know what else it could be. It does sound pretty cool though, like I got something under the hood.