Wind Whistle at 50+mph W111 Coupe
 

I have a prominent wind whistle at hwy speed in my 250SE coupe. With windows/sunroof closed and antenna down I can faintly here it. With window open it is louder. With sunroof open and window open it is much louder. Sounds like it's coming from in front of windshield but hard to pinpoint. The seals at windshield, windows and doors have been replaced 5-10 years ago so they in good order even if not factory.
The thing is, I am familiar with the sound of air leaking past door seals but this sounds louder to me and harder to find. I searched to no avail...has anyone out there already been down this road?

You sure it's not the vent/wing windows? Push it closed when driving to check. It's got an adjustment rod, you can make it a bit tighter.

Does the noise change when you turn on the wipers?

My 99 Ford Ranger has a noise that goes away when the wiper is at the limit of it's sweep. I think the noise is coming from the drivers side of the hood where it meets the cowl because the hood is slightly below the cowl. I'll shim the hood sometime. . . .

A quick way to test things is to use blue painters tape at various body seams / areas to smooth out transitions.

Thanks for the replies. I don't think its the vent windows because they are usually open. However I will experiment more with this.

I thought it might be wipers as well but then I read so many comments about how quiet these cars are on the highway and figured there was no way this whistle was normal! I will experiment with tape, window configurations, and wiper removal and see what happens.

Wind noise
 

Tomguy will be correct, what happens is when you in crease speed
it creates pressure on inside of windows, and any small gap will become
slightly bigger with increase in speed.
A slight whistle noise is usually created by a less than thirty second of a inch gap. you will find it..