ok so ive owned my 2010 XB for about a month now and ever since I got it ive noticed a quiet but strange noise and you can only hear it at idle... while you are driving it goes away and you cant hear it with the windows up so its faint... its not a whining or clicking... the best way i can describe it is like a frog almost sounds like raaant raaant raaant... its a slow noise not fast... I replaced the belt but it still does it... If i have the ac on it goes away if I step on the gas a little it goes away??? It has 43K miles... I also changed the coolant and oil no leakes anywhere... anyone have any ideas???

 

ok so here is a vid i just took from a cold start... you can hear it really well about 30 sec into the vid

 

If you can tone out the engine noise it actually sounds like you are outside at night near a river.... frogs and crickets.

I can hear the noise but have no idea what it would be. Based off of what you describe and what I hear it has to be driven off of the engine rotation because it has is consistent in the interval of the noise as well as you the noise changing while you accelerate, etc.

 

My 2005 had a similar noise (not quite the same), but it turned out to be the air conditioning pump. Faint noise that would disappear when moving?? Took quite a while to isolate noise due to engine noise in background.

 

oh well it still does it a little I checked everything I could... the belt is new the water pump is fine and the ac blows cold so im not going to worry I appreciate the comments tho

 

water pump? alternator? have someone step on the gas pedal to hear if the pitch and frequency change. to bad this is drive-by-wire, otherwise you could open the throttle body manually.