Greetings from Canada,
My wife and I in 2020, purchased a 2008 Chevrolet Cobalt with 20,000km. Not kidding. Literal old lady car!
There is a sound coming from the windshield edge of the dashboard. It sounds very similar to a Geiger counter 😂.
Only consistently occurs at highway speeds. Air gap somewhere?
We have no idea what it could be.
See attached link for sound video.
It could be. Put some paper towel above the dash and pour water from outside on that edge.
We tried the paper towel idea. Ended up dry. No visual leaks either.
Could the windshield be poorly sealed at the bottom?