I had taken the truck in for this before. C-pillar on the passenger side was wet by the rear seat and the floorboard on that side. The dealer said the drain was clogged. Fast forward a few months and I see the same leak, but higher up where the seatbelt comes out of the pillar today and it's really bad. The headliner had a little bit on it but the cover with the alcantara was soaked. All of the carpet was soaked all the way down. Not much I could do in the driving rain so I grabbed a towel and did the best I could. I traced it down to the drain tube that's in the rear of the moonroof guides underneath the headliner. The coupling that connects it to the rails was fine, but where it connects to the drain tube was not sealed. Maybe this was heat shruck or something, but I had to put some RTV silicone on it to seal that up.
After I came home, I found the other side was wet but all the way back by the d-pillar behind the quarter panel glass. Following that down and lifting the cargo cover the subwoofer was partially submerged! So after drying all of that out and finally fixing the other side as well it's water tight again (verified with a water hose). All I had for pics was my phone but here's the line where I put the silicone on it and where it connects under the headliner.

 

For reference, the hose in the headliner at the lower left is one of the places the rear grab handle bolts to (this is the left/driver's side). The white thing at the top is the air bag curtain.

 

could you hear water sloshing around? We just had some heavy rain a couple weeks ago, and I've got water sloshing somewhere, and I cant quite figure out where it is...anyone experience this? I think its either in the roof on the drivers side, or maybe in the c-pilar?

 

No sloshing sounds.
It rained again today for a while, hard at times and the fix is holding up just fine.

 

I don't know if i have the confidence to start tearing it apart...i may have to just take it in. Is this a warranty issue?

 

If you have warranty I'd take it in. The only reason I fixed mine is because they didn't "do it right" the first time.

 

Thanks for nice information...thanks to all..I will visit again to know..

 

thanks for sharing. this info is good to know if ever I run into this problem.

 

how hard is it to pull the headliner? I'm having this problem, water leaking in rear right passenger grab handle above window. part of the headliner is wet and the c pillar is soaking. porsche dealer says is has been a common problem and they have a close by body shop do all their fixes. they said if its an easy fix 250-300$. an upholstery shop says they'll pull the headliner for $125. id really like to be able to do it all my self, but am scared to break anything... would you be able to provide a step by step? maybe with pictures?

 

i have the same issue , but from the passenger side,.. can u share more pics pls...
its killing me ,.. can explain step by step , thanks

 

I had the same issue this Monday after heavy rains and then I got this insane noise out the back of the truck. Sounded like I was running straight exhaust. Bizarre. Really sounded bad. I was so worried I took the car in first thing Wednesday morning with no appt and they brought the truck on the back. 10 minutes later they come out and say my sub woofer is underwater causing all the noise. They pulled it out and drained the water and ordered new drain hoses and sub woofer.

 

I'll try to get something in this evening. Not that hard to do.

 

These should help, depending how in depth you want to go.

 

The rear roof cover where the dome light is in the very rear just pulls down. Hope that helps. BTW, mine are still leak free.

 

Wow, underwater heh? Jeez I better check mine.