After a recent heavy rain my rear passenger side carpet was absolutely soaked. I did some reading on the forum found the sunroof drain firewall fix, and figured the water had made its way to the back row because I was parked on a hill. After doing the fix, I decided to remove the rear bench seat. Beneath the seat was also completely drenched. Any ideas where this water could be coming from and how to fix it? Rear sunroof drain tube?

 

Hey man, I'm right there with you, I removed the seats and noticed that a majority of the water was under the floor of my rear seats ('11 coupe), albeit a little water underneath the rear and front passenger seats. You can check out my recent post for a video on what I'm seeing (the water seems to be concentrating from the small hole next to the door). I am trying to see if there is another sunroof drain on the back, but no one really responded yet. Hopefully we can soon figure this out

 

Well.... I tore it all apart and found that it was in fact the rear sunroof drain tube. The same style grommet used on the firewall can be fairly easily accessed from the trunk my removing the trunk lining.

My grommet was clogged, drain tube filled with muddy water, and a major leak originating at the sunroof connection. Due to the amount of water on my floorboard, I made the decision to pull the carpet. I would like to point out that the floorboard is not flat beneath the carpet; there are several areas where water pools up. In some places I had roughly half an inch of standing water. There are two Styrofoam pieces that make the floor seem flat from the carpet level, but they do not allow accurate perception of how much water you are dealing with until you pull the carpet.

I will include some pictures and a more detailed write-up when I reassemble in a day or two

 

How did you know it was your tubes, specifically, the right rear one, instead of the firewall? Was the water not flowing freely through the bottom exits on the ground? I just finished taking out all 4 firewalls, cutting the baffle out and adding zip ties but now I'm getting leaks on the areas other than my right rear?? Should I take a can of compressed air and blow down the tubes from the sunroof ports, or clean them another way? Glad you got it fixed and, in the meantime, I will absolutely be looking forward to your write-up!

 

Anyone tackling this and reusing the factory grommets NEEDS to do the straw trick. 99% of the time the rubber foam gasket of the grommet is breaks/deteriorates and if not fixed it will leak again no matter what you do.
The straw takes care of that by moving the drip point farther out so the drip doesnt travel backwards which from factory it does.

 

What is the straw trick?

 

 

I chopped the tube entirely and ran new vinyl tubing deep into the firewall. Only thing that's going to flood my car now is if the firewall drains get completely blocked up, so I'll periodically clean them.