Grand Prix GXP with Sunroof - Water leaking from roof

mcotter11

Need thoughts about water intrusion. I have had 'water tests' done multiple times by a dealership, the sunroof seals have been replaced, the 'channels' were cleaned... We can't figure out where the water is coming from. The area of the headliner that is wet runs along both the driver and passenger sides between the sunroof and the door frame.
Sometimes the headliner looks wet only above the door, during hard rains it is wet up at the sunroof area. The back interior lights have filled up with water but only once. There are channels on the roof that run parallel to the sunroof that have seals in them but I can't find a diagram that tells me what these are. Could the water be coming in from these channels rather than the sunroof? There is also the XM radio antenna (horrible placement BTW, when the sunroof is open, the signal goes wonky) but the water stains on the headliner tend more towards the front of the car.

imidazol97

I would suspect the seam between the door panel/rocker unit and the center roof unit.
Have you checked all 4 drains to be sure they're not kinked or blocked by debris.
Fronts sometimes give trouble where they go through the floor pan to drain under
the car.

It looks like you need to learn how the roof panel can be rotated to be removed
from the car. Or have a shop do it to take a look from the underside of the
roof for the source of the water.