Goes away when I open the window, or leave it ever so slightly open.
Where do I start looking to silence the noise?

 

Was the windshield replaced (I assume it has). If so check the top of the A Pillar for that little piece of moulding. Mine was loose. Once it was reinserted properly fit, the noise went away.

 

+1
Older cars had a "felt" strip...newer gen1 had a foam gasket, as does the replacement parts that fit under the moldings to seal it...

Window installers don't carry the a pillar moldings or clips...the break 75% of the time when a window is changed...then the "make it work"... Result is it whistles, or flies off a few weeks later...
Door seal might be bad or the window/door miss alignment... But the a pillar moldings would be where I would check first.

 

Yes, definitely check out that molding and then the seals if it persists. You can purchase some here if needed.

-Luccia

 

The windshield was replaced, several years ago. The whistle started a few weeks/months ago. The whistling stops if I open any window, or the sunroof. I have looked at both trim pieces at the a-pillars, and not sure if that's the source.

Looking for other suggestions.

 

Reset the door gasket into the front a pillar or see if the window for some reason does not seam all the way into the seal. If the window motor or dip function seem to working properly.

Thanks

 

I looked at the window more closely, it seems that the gap at the leading edge is wider at top than on the other door. Almost looks like the window is leaning back. Gap at rear of the top edge is slightly wider than at the front..is there a way to raise the rear of the window a mm or two?

 

Bet the window need adjusted . It can be moved around on the connection to the regulator.

https://www.northamericanmotoring.co...ndow-leak.html

 

The window definitely needs to be adjusted. However, as an interim solution, I took a length of 1/4" tubing (like the stuff used for water supplies to refrigerators) and pushed it into the channel of the door gasket. It has significantly reduced the whistle. Now it just sounds like air rushing around the car, vs the incredibly loud, earsplitting whistle I previously had. But as I mentioned earlier, the gaps around the window are not even and the largest gap is a the top of the leading edge of the window.

 

That will work in the mean time. Its needs adjusted, you will have to pull the door card off, and get to the mounts on the regulator. then move the glass a hair towards the top and front most likely.

 

There is a channel lock plyer that has a very large jaw for plumbing. Look in the plumbing department in the tools section. It is skinny and the same size as the official tool. But better yet you can also use it for other things and buy it today. I had this problem on mine after I.replaced the regulator and never adjusted it correctly. It took me about an hour to learn the correct position of the window. Use the other side that does not have the air leak as a guide.