Help! My 2001 Rodeo has recently developed a loud whistling/humming noise. It has about 120k miles. The noise starts at about 65 mph and gets louder the faster you go. The noise also lessens when you open one or both of the front windows. On a recent road trip, my wife and I were trying to find some magic combination of the windows up/down to make the noise stop.
The noise is a loud humming/buzzing noise. It doesn't sound like the wind whistling through a hole or anything like that. My wife (the mechanical engineer) thinks it's a part that's vibrating/resonating quickly enough to make this noise.

Any help would be appreciated,
Trevor

whistling sound typically means a leaky intake manifold gasket, but I doubt you could hear it going 65 MPH....

I recently purchased a 2001 Rodeo Sport and had the same problem. I fixed it by first pushing against the entire inside perimeter of the windshield while the noise was happening. I noticed it lessened near the rear view mirror. Ipulled over, checked the gasket on the outside and found that it had slightly slipped up. I pushed it back into place and no more problem. I should probably find some sort of adhesive to keep it in place because now , a month later, I noticed it again.

Palomo's post jogged my memory. We had the windshield replaced a few months back. Last week when I was on the freeway, I pressed hard on the windshield and the noise got louder. I'm sure that's what it was. I already have a huge rock chip in my brand new windshield anyway. Good thing the auto glass guy is a friend of mine.

Thanks,
Trevor