I know there are a few topics on these, and I have read them, but have not seen the specific problem that I found.

From the other topics I have seen that bumper vents, boot laches, and roof to rear panel seams are mostly responsible for the leaks. I have already sealed the joins between the roof and rear 3/4 panel at the top of the hatch, and have tightened & sealed around the hatch struts. That stopped the leaking on the right side of the car, but left side continued to leak. 

To investigate I took apart the trim and poured water down the roof & around the c-pillar window. Eventually I found that the leak is coming upward, from a gap in the seam between two body panels:

I can't imagine it's the vents, as this is high up, and I was pouring water on the side & top only amd the car was stationary. It may be the C-pillar window having developed small cracks, but from the inside it's not the cracks that leak. And the seam at the top of the hatch, between the rear panel and roof, has been sealed, as have the struts that carry the rear hatch.

So I'm at a loss. Has anyone seen something similar?

The roof joint sealing looks like it has failed

On 11/15/2025 at 4:38 PM, Neb_engineer said:

The roof joint sealing looks like it has failed

Is there a gap between the roof panels where the roof rack rail is, or only at the back?

Guess my next question would be how to remove that rail to have a look.