It's pretty loud inside the car, but very hard to hear under the hood. For lack of a better description, it goes woooOOOO. :woot: In gear, out of gear, doesn't matter. It goes up in pitch as the revs go up. The exact same noise also comes thru my radio via the iPod adapter, but not on regular radio stations. I can still hear it with the radio off. (I had a Suburban once that made a similar noise....it was normal noise from the fan driven by the engine. This sounds like that.) It is loudest at idle, and isn't noticeable at speed (unless I have the iPod on.) The car is also getting a little difficult to start. It turns over fine, but it's like it won't catch. The battery is only 6 months old and the battery light does not come on. Any thoughts/suggestions?