Hello everyone, recently purchased a 2013 XF 3.0 AWD and I'm absolutely loving it. But the first issue has popped up:

During heavy rain I noticed water forming around the center dome light and dripping over the gear area. I spotted it quick enough to avoid any damage and once dry I've begun investigating the possible cause. From my research here and other places I've found the most common cause of sunroof leaks are clogged drains, but that doesn't appear to be the case here - I've tested by pouring water down them and they seem to drain fast enough.

The rubber seal around the glass itself doesn't seem to be the issue either, it appears to be in good shape and is fully seated.



Further inspection revealed there is a seam where two parts of the black plastic sunroof frame meet. It appears this seam is where water is leaking through, and I can see what looks like the possible remnants of old silicone. In the photos I've uploaded the seam is marked with a yellow marker, which was actually there on the car already. My question to the experienced community here is - is it typical for this yellow mark to be there? My guess is that it was put there during assembly to mark where to add sealant, and has simply deteriorated over time? If it's not typical, maybe this was repaired previously and similarly has deteriorated?

My hope is that I can add some new silicone or other sealant along this seam to stop the leak.

 

Updating here in case anyone happens to experience this same issue in the future - I believe I have fixed it. My theory is that the tension of the pop-up windscreen was causing too much upward pressure on the frame, causing a seam between two pieces to widen slightly, allowing water egress from the drain channel. Maybe the windscreen was at one time tightened too much, or maybe it had gotten knocked out of alignment over the years. Removing the wind-screen and siliconing this seam appears to have stopped the leak completely. In the photo below you can see where I add silicone to the seam, and can also see water around where the windscreen hooks into the frame. That square opening is where I believe the tension of the windscreen was concentrated, hence why the water was emerging there. In the future I may test adding the windscreen back, but I don't expect to miss it much anyway.

As to why this seam was not watertight to begin with I'm not sure, and am hoping someone can take a look at this area of their XF sunroof to see if it looks similar, or more well-sealed.