Strange Vibration/wind noise

[lojeff]

If I am driving at highway speeds and open 1 or both of the rear windows, but leave both front windows closed, I get a very loud vibration or wind noise. If I open one of the front windows an inch or so, it goes away. It almost seems like pressure is building up in the car.

Has anyone ever experienced this?

Can some of you try and see if this happens in your 4runner as well?

Any suggested solutions? I used to have a blazer which I drove all the time with the back windows open with no problems.

 

[dancojgl]

The phenomenon is called a "resonant cavity."

Try blowing into a glass beer bottle...Hear the boat-horn noise?

Now try something with a larger opening, say a mayonaise jar. You won't get that boat horn sound.

Same thing's happening in your 4Runner. Lowering the front window a bit is disturbing the walls of the "cavity" enough to prevent resonance. (Actually, lowering the window only changes the resonant frequency of the cavity--drive at some other speed or direction to the wind and you may be able to get it to resonate again, but the pitch of the sound will be different...)

--Dan

 

[ToolmanJohn]

Has happened on several vehicles

A few of the cars I've owned had that same quirk. I haven't had the 4runner do it, but notice that if only the front side windows are down, the wind noise is very loud. I have to open a rear window to change the level of noise.
On a different note, my rear seat belts oscillate at highway speeds. Even when I lock them into the buckles!! I'm thinking of putting pads on then to make them heavier. I don't know if it will get better or worse, but have to do something now that nice weather is here and driving with the windows down is more common.

 

[NoDak]

man i hate that. the 3rd gen moonroof fully open and no other windows open would get a bad case of that, ended up only opening it 3/4 way. i think the new runners also do it, but not as bad as the older gens did.

well at least for me.