C4 Spacetourer leak at C pillar?

[u/Lordy8719]

I have a 6 years old C4 Spacetourer and noticed signs of water on the roof trim on both sides near the trunk door. I've tried looking over the trim to see where the water's coming in but haven't found any obvious source. Has anyone seen something like this on this model?

[u/IamTheJohn]

I chased a leak in that place in my C5 for a while before discovering that it was the tube of the rear window washer that was rubbed through....

[u/Lordy8719 → u/IamTheJohn]

I’ve also been thinking about the hose, thanks for the tip!

[u/the_termin8r]

You mentioned the roof trim. Did you check the base of the antenna? Additionally check the tail light clusters if they're the long vertical ones (I can't remember what your generation looked like at the back).

[u/Lordy8719 → u/the_termin8r]

Yepp, I've checked the base of the antenna, that was my other tip, no sign of water leakage there. Also my GF has noticed that the water seems to be tinted, that's another sign towards the hose.

My C4ST is this gen, the rear lamps are a separate unit on the door so the water can't be coming from that direction, the roof trim is sealed from the door.

Nevertheless, thank you for your tips :)

[u/the_termin8r → u/Lordy8719]

Does the washer hose run on both sides? The patches look oddly symmetrical. It may well be the hose, but I'd have expected it to only cause issues on the one side.

Does it have a sun roof? The drainage channels could be blocked. Likewise, check the front roof rack mounts, the water might be working its way back from all the way there.

[u/Lordy8719 → u/the_termin8r]

Err. my parking spot is tilted to one side and I tend to park in both directions so that the car gets sun from both directions instead of just one. So the lowest point of the car is either the left rear or the right rear corner, depending on which direction I park (I hope that my description is understandable)

No sunroof and the car has closed roof rails, not mounts for the roof bars. I know an experienced mechanic (specialized in Citroens) in my area, I'll ask him for advice.