Hardtop wind noise

vroomvroomman

Zorg Addict
Supporter
Dutch Zeds
Joined
Dec 5, 2025
Points
48
Location
The Netherlands
Model of Z
'99 Z3 M43 1.9
Hiya everyone, I've been having an issue with my hardtop which has excessive wind noise near the rear of the driver side window at 80+ kmh. The passenger side window is quiet. I've already tried the adjusting screw at the bottom of the door to tilt the window inwards, but the screw was already fully outwards (which then turns the window inwards). I also tried to move the screw from left to right, but the window had no movement in it at all. The screw for the front smaller window did actually tilt the window properly, but the rear does nothing.

not that it matters, but the car is a 99 facelift z3, with a hardtop from 01. Also worth noting that I spent an entire day trying to get the alignment of the hardtop height right, but the wind noise always stays. You can also just see that the driver side window is much more outwards then the passenger. Driver also leaks when washing the car (also with softtop). The wind noise is most noticeable with the hardtop, but it's also there with the softtop, although that gets pretty much drowned out with all the other noise.

Does anyone have any idea on how to fix this? Going on a road trip in a month and would really like to take the hardtop and not go deaf due to the wind noise :)
 
I wasn't aware that was a thing!! I'll go ahead and try that out when I'm home tonight. Won't that create a panel gap though if my door is already flush?
 
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I remembered reading this a few years ago :-

The "Rope Trick": If the seals are permanently compressed with age, many Z3 owners thread thin, flexible silicone tubing (or round foam cord) inside the hollow rubber seals. This "pops" the seal out, giving it a much tighter contact patch with the window glass.

I must add that I never tried it myself.
 
I'll try that too, though comparing the driver and passenger side, it seems that the passenger side looks more compressed (with door open) then the driver side, it's like the glass is just too far out on the drivers, but it's a pretty good tip, considering new rubbers are crazy expensive.

I removed my door card again todauy and checked out the window sliders, took one out, looked fine, wanted to put the new one in only to realize I got the wrong part (have had it for a while). Tomorrow the correct sliders are arriving then I'll replace all 4.

Also noticed that when the door is open, you can push it down like 1-2cm. After looking further it was the window slider in the long metal rail that is just completely broken, which allowed for some play. Hopefully this fixes my wind noise issue too.

I'll keep you guys updated when I fit the new sliders tomorrow or somewhere this weekend!
 
Alright so I've replaced all the window sliders, and I believe as an added bonus point my passenger window rattle is gone, and the windows go up and down quite smoothly now. When I adjusted the door latch earlier thoug, I saw that it created a panel gap, so I reverted that.

I don't believe the wind noise is fully gone (can't test it untill I got the hardtop on), but I did notice another interesting detail.

Both windows have a bmw logo and some other text in the back corner, I noticed that the one on the passenger side was way higher up then the driver side. So that will be my next quest; adjust the window height. I remember reading somewhere that it's possible to do that. When you have the door card off. I'll have to check TIS just to be sure though.

Safe so say that changing the window sliders makes a huge difference though!

Update:
Found it already, need to adjust screw #1
1782109371376.webp
 

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Another update:

I've adjusted the screw (#1 in pic above) so the window sits a lot higher. Water still leaks in through the gap of the two seals, but I'm not too worried about that, it's minimal. I did a test for before and after and while before the water would come done on the inside of the window, now it only leaks through that one seal when spraying water directly on it. Unfortunately can't tell if this actually reduced wind noise until I got the hardtop on in a week or two, so I'll check back then.

I also turned on a feature using NCSExpert to drop the window a tiny bit when opening the door (E36 coupe/Z3 Coupe feature?), this should help preserve the rubbers a bit by releasing some tension when opening the door and create a better seal.
 
I also turned on a feature using NCSExpert to drop the window a tiny bit when opening the door (E36 coupe/Z3 Coupe feature?), t
My E36 Convertible does this and my M Coupe did that. Didn't know the Z3 could be set to do this?
 
Me neither! I was reading through the options in my modules using ncsdummy and I saw this feature so I turned it on. Also saw a convertible function & drop window when opening/closing convertible roof, but those unfortunately don't work (even though I do have an electric roof, but it's prob there for the E36 convertible).

Don't have ncsdummy by hand, but from reading the ncsdummy translations file I believe it was this one: FH_ABSENKUNG_SPERREN (Disable drop power window when opening frameless coupé door). It was set to Active, meaning it's disabled.

Looking further in the translations file I also found these:
FH_KURZHUBDELAY_ZU (Delay to raise power window when closing frameless coupé door)
KURZHUB (Distance to drop power window when opening frameless coupé door)

But I have no idea if these are actually available in the Z, since I'm not connected to my car's module right now.

NCSExpert/Dummy is fun (and dangerous) stuff!

Unrelated, but using ncsexpert/dummy I also programmed my euro spec car to beep like american spec cars, my neighbours hate me now but it beeps!
 
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