While I was driving today, I decided to put down the rear two windows. Once I hit about 40 mph, I got this weird vibration from the air coming in. It almost sounded like the noise helicopter blades make (a repetitive thumping). The faster I went the louder it got, almost to the point where it starts to shake the car. Once I put the windows up it stop. I put them back down and it happens again. WTF? I put the front ones down and it doesn’t really happen (only very slightly). Anybody else have a similar problem like this? Everything is tight back there. The rear deck with the speaker, head rests, seatbelts, etc. I was the only one in the car, perhaps with a passenger in the back this wouldn’t happen? I have no idea why or how it could make this loud noise. Anyone?

 

It is a normal dynamic of differences in air pressure inside and outside cabin

 

yeh had the same problem.... scared the crap out of me. i showed my brother and he says all cars do that so take that fwiw.

 

open the sunroof...it will go away...........

 

My thoughts (which may be wrong, so take everything you read after this point with a grain of salt):

I think what you are experiencing is a testement of how "tight" the TL's cabin design is. My guess is that you are getting a "parachute" type of effect from the air being drawn in from the sides and getting trapped and compressed in the rear of the car. The amount of distance from the "air intake" from the side windows to the rear window is pretty short (only a couple of feet).

Opening the front windows and having the rears closed still has a "parachute effect", but the volume of trapped air is consderably larger - you have the entire back seat area combined with the rear window area. This possibly results in a lower overall characteristic frequency or amplitude.

Or, I could be totally full of B.S.

¿GotJazz? - Now scaring the feces out of fluid dynamics and aerodynamics instructors nationwide.

PS: Don't ever sit me in front of a computer when I have nothing better to do!

 

This "vibration" is COMMON in ALL modern sedan's with good aerodynamics. I first noticed it on my 1997 740iL. To resolve, simply crack the front windows (slightly) as well. The air flow fomr the front (minor) opening will provide ample wind channel disruption to stop the vibration from occurring.

 

My 94 Accord does the same thing. Opening the front windows or sunroof does the trick. Haven't tried it on my TL, but now I guess I don't have to.

 

yes i tried the same thing... sun roof was closed, front windows were rolled up... and then i rollled down the rear windows and iget this noise man... shit it started killin my ears.

 

that noise drove me crazy the first time I heard it!
told my kids, CLOSE that window NOW!
I then locked the windows, and open the sun-roof at an angle to let some air out, it improves circulation.

 

My wife told me the same thing last week. I thought she was nuts, but a few days later I put the front windows up before the back and aarrgghh! Not a good experience. I have had similar things happen in other cars, but it makes a very strong "don't do that again" impression in the TL.

 

My wifes SUV does the same thing.

 

Ok, good. Thanks. Im glad to know it is common then. This being my first sedan, having only sports cars in the past, I wasn't aware this happens. I'll make sure to open the moon roof or front windows before I open the rear ones. Man does it get loud, especially if you open the back window's doing 60-70 mph. Wow......

Thanks again