Help me solve this wind noise issue on the freeway

[luke87gt]

Hi guys, I'm hoping this problem will be obvious and some of you guys may have seen it before:

Ever since buying our 2006 4Runner last year, we’ve had this wind noise problem coming somewhere from the driver-side back half of the SUV, only while on the highway above 60mph or so. It sounds like something is loose (like weatherstripping or a mudflap) and smacking the body or wheel well continuously by the wind. I can describe the sound as fairly high frequency (5-10Hz, in other words I can hear whatever is loose being smacked around about 5-10 times per second). Imagine if you pinched a good length of the seat belt outside the car while rolling up the window and imagine that length of seat belt flapping in the wind on the freeway, that's what it sounds like.

Unfortunately, the problem isn’t obvious. The weatherstripping looks good. The mudflap is tight against the wheel well. I’ve driven on the highway while maneuvering the driver-side side mirror to see if I could see anything obvious whipping around by the wind, but I can’t.

I was thinking about removing the rear passenger side mud flap to see if the noise goes away for trouble shooting. But first, I’m hoping someone has experienced this and can shed some light? Thanks.

 

[LOSTR4]

Try the front fender liner...that can be a sort of ventriloquism believe it or not...another place to check is the your skid setup underneath....or your spare tire...

 

[Levinz11]

Man I'm boggled by the same issue. All moldings seems tight. It happens to me only above 70 and on Wednesdays and Sundays. Grrr

 

[luke87gt]

Try the front fender liner...that can be a sort of ventriloquism believe it or not...another place to check is the your skid setup underneath....or your spare tire...

It may be worth a look but it seems to be coming from the back half of the car, not the front.

When you said ventriloquism, I'm reminded of a problem I was chasing for months in my 2001 Lexus GS430. I was getting this THUD coming from the rearend when accelerating hard from a stand-still. It took months of diagnosing the culprit which turned out to be a bad motor mount.

The broken mount allowed the engine to rotate and when it would rebound from it's highest level of rotation, the energy would get transferred along the driveline causing the thud in the back of the car (of course the problem was in the front).

 

[V8Man]

I have had the roof rail screws loosen, they don't fall out but if the cross rail is in the right place they rattle.

 

[luke87gt]

Problem Solved: it was the loose roof rack screws

I'm not sure how it happened for two reasons

a.) I've tightened them in the past and can't believe how quickly they've loosened again. I had assumed that since I tightened those screws not too long ago that they were still tight.

b.) I was nearly certain that the noise was coming from the lower half, certainly not from the roof. One of those ventriloquism issues where the noise somehow gets transfered to an area other than where it originates.

Thanks for helping me brainstorm guys!