I have been hearing this noise that is louder under load of the motor. around 1500to 2250 rpms it makes a shhhhhhh or cold air intake noise. I have been hearing it for a while and it drives me nuts. I know its belt related because if I loosen up the alt. it goes away but of course the belt is not tight. I know its not just my car because my old xb did it, and my moms xa makes the same noise. Mine is just louder. I changed belts and noise is still there. Anyone know what causes it. Almost sounds like a pulley brg going bad, but 3 xb/xa motors I have make it. Mine is just the loudest.

Noticed the same on mine a week ago, though I think my power steering pump is going out as well. I'll let you know after I take mine in to the stealership for warranty work.

Any solution to this? I'm going to try to address this same problem soon on mine. For all the people that have posted there has never been a definitive solution to the 2000 rpm rattle. Some have said power steering pump or water pump. Another has said the exhaust gasket. To meet is sounds like a loose pulley but who knows?

Go get a can of sylicone spray. Spray it on the belt and test drive it and if it doesn't stop then you have eliminated the belt. Then pull off the belt or just grab each pulley one by one and move it up and down to check for looseness. If nothing is found try spraying each pulley near its bearing with wd-40 or a similar lubricant. if it is the water pump none of this will stop the noise but you should be able to feel a looseness in the pulley if it is bad. make sure no one turns the car over well you checking any of these items.

Same here. Accelerating between 1500 and 2000 rpm (approx) produces a noticable "shhh" Is it pretty common to the xB's?
Shouldn't the dealers be aware of this problem? Class action comes to mind ;)

Vacuum leak? Those can cause really strange noises.

Just put Unleaded Plus gas into my box, after reading recommendations on the internet and the noise is gone. I am really hoping that was the crappy gas last time or it may indicate something horrible with the engine.