StratfordShark

My S4 has developed phenomenally loud wind noise. Above 60 mph there's a kind of clattering noise which seems to come from windshield rail over my head (it's RHD) and builds in frequency as speed goes up till it's a continuous clattering/buffeting noise.

I say "mystery" because it only started yesterday, near end of trip where I had done a couple of hundred miles at those kind of speeds without any similar noise.

I did install the GTS filler strips years ago, and they cut down on windshield noise dramatically, but it was nothing like as bad as this before! I do have a new upper window seal ready to go in as I am aware of wind noise around top rear of door on my (right) side.

Has anyone experienced anything similar? I haven't heard anything like it in 12 years owning this car. Any ideas please for things to try to isolate the source?

Thanks a lot.

jchasty

Hi, what are "GTS Filler Strips?"

Thanks

John

FredR

Did you put new batteries in your hearing aid?

The only thing that comes to mind is to check your sunroof has sealed correctly if by any chance you had it open during your run due to the nice weather the UK has experienced [apart from the day the test match was rained off!].

Jerry Feather

Here is the whole story, as told by me. All of the 928 are designed with a significant gap along the sides of the windshield (WS) between the surface of the glass and the metal WS trim along the sides (up and down the A-posts). The original purpose of the gaps is part of the overall rain gutter system. The gaps gather water off the WS and pass it upward in the gaps to a small opening near the upper WS corners and under the WS trim and from there the water passes into the rain gutter that is hidden under the aluminum trim that passes over the car at the top of the doors.

I am pretty sure that very early on the Factory learned that the small openings at the top corners of the WS were making noise that annoyed some customers; so they began installing short pieces of rubber weather stripping glued into the corners to close the rain gutter openings there. I suspect there may even be some kind of service bulletin and maybe even a kit for dealers to close the gaps, but I have not seen it.

Then, I think in 90, the Factory began to fill the entire gap from the bottom of the WS to the upper corners with some kind of rubber goop; and finally, with the GTS probably in 92, they began to fill the gaps with a nicely formed and tapered rubber weather striping like material that even has a tiny sort of dart that is pulled through the rain gutter opening at the upper corner. I suppose those may be glued it, but they may only be stuffed in. Those are what he is calling the GTS filler strips.

I designed and fabricated some plastic WS Gap Filler Strips, but have found that there is some kind of flaw in my design. I had a couple of reports that one or the other of my strips came out at speed or maybe in the rain, or both, and then one of mine came out of my 82 at about 95 mph between CA and Las Vegas. I haven't figured out why since my design has them pretty well held in with spring pressure; but apparently not enough to over come the effects of air flow and the resulting pressure differentials; and I think my spring loaded design may also contribute to a kind of reverse barb effect that with wind and vibration causes then to simply work themselves out of the gap.

StratfordShark

Thanks Fred. In fact the weather in the UK has been too sunny to use sunroof recently! On a test run earlier this evening I checked roof was fully closed, and it's closing as normal. If I drive with roof fully open I hear the same noise (only apparently quieter because of noise through roof aperture) as with it fully closed. In any case I didn't operate the roof from start of trip yesterday to the point where noise suddenly started or at least I suddenly became aware of it. Oddly it started right after a very short burst of heavy rain. In fact at first I thought the noise was from unusually heavy winds but apart from that shower there's not been a breath of wind. Wondered if it was a wiper noise provoked by using them at full speed during that shower, but there's nothing loose about the arms or the wipers.

FredR

AC/DC at 90DB will cure it!

I get an annoying noise on my Cayenne from the roof- for some reason the opening mechanism on the panorama sunroof suddenly decides to open the roof a smidgeon and then I get a wind type noise then opening it and closing it cures it. That was why I suggested taking a closer look at the sunroof with a view to ensuring it really is fully closed.

Whatever the root cause something had to change suddenly as in like movement, opening or snapping off. Good luck with the quest.

Petza914

Look under the car for something you've picked up like a plastic bag stuck to something that starts flapping at a certain speed

Speedtoys

s/gooo/strip/

Fixed it for you.

Its just a simple rubber strip that sits in there.

Speedtoys

See if the windscreen top trim is lose somewhere, and the wind picks it up.

StratfordShark

Thanks for suggestions Speedtoys and Petza1914 but I'm still baffled.

I thought it might be the sunroof motor cover which I discovered was not inserted in tab on one side (it had dropped out a few days ago and I thought I'd reinstalled it properly) but still same on test drive — as if a rock band drummer was on roof!

Nothing caught underneath, and no loose windscreen trim. It's absolutely baffling but honestly the noise is so bad I can't imagine going on any trip above 60mph.

Will keep investigating.

BRB-83-911SC

Check your cowl/wiper motor cover - maybe it has come loose. I know it's not in the location you hear it coming from, but noises in the interior can be tough to source the location. Just a thought.

StratfordShark

Thanks Brian, I'll check that area.

Edit: Checked the cowl, and all firmly clipped into place.

928Myles

Last resort:
Put some earmuffs on and go for a drive up to 100mph. What is making the noise will have either left the car or become much more obvious.
Either way, it should be an simple diagnosis from that point on.......

Myles

StratfordShark

Worth a try thanks, though in speed camera saturated U.K. 80mph may be realistic max!

StratfordShark

I thought I'd use an ultrasonic leak detector I have (originally bought to see if I had any leaks allowing in moisture when I was getting a bit of condensation inside in certain weather conditions — found no leaks).

It's very sensitive and accurate, localising leak to very tight area.

With the transmitter sitting on centre console, I found no leaks whatsoever around sunroof seals or windscreen, but there was a leak on right (driver for me) side from one area of the upper window seal. This is actually a seal I have ready to install as I was aware the glass didn't fit anything like as snugly on that side as passenger side. No rattles, but seal channel didn't wrap tightly around glass.

I wonder if this is the cause, and that seal leak is creating some kind of turbulence?

Need to install seal anyway so won't cost anything to try.

PS the kludged install of rear of scraper seal was work of previous owner, and I've lived with it for twelve years but have new seal to replace it.