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Oy, cabin is leaking again. First saw a puddle in the driver side floor mat, then noticed water near the OBD port and hood release…ultimately traced up to a pretty damp Driver side A-pillar.
Both of my front sunroof drain tubes (driver and passenger) are rerouted to the A/D drain in the passenger footwell, so I know it doesn’t have to do with those firewall plugs.
Are there common issues with the sunroof drain inlets? Connections that loosen up? Things get clogged?
Im about to open up the driver A pillar and probably the headliner in that area too, so any tips on what to look out for is much appreicated
Oy, cabin is leaking again. First saw a puddle in the driver side floor mat, then noticed water near the OBD port and hood release…ultimately traced up to a pretty damp Driver side A-pillar.
Both of my front sunroof drain tubes (driver and passenger) are rerouted to the A/D drain in the passenger footwell, so I know it doesn’t have to do with those firewall plugs.
Are there common issues with the sunroof drain inlets? Connections that loosen up? Things get clogged?
Im about to open up the driver A pillar and probably the headliner in that area too, so any tips on what to look out for is much appreciated
There has been a couple similar posts in the G37 Reddit sub, user re-routed the sunroof drains to the AC drain, but there is still leaking in the a-pillar. You have eliminated the seal around the door correct? Our cars are 10+ years old, so I suspect that the door seals will start leaking soon due to shrinkage and dry rot. Also, if you pour water into the drain with a small cup, does it exit through the AC drain properly?
How easy is it to get to the top part of the drain near the sunroof as you can't really see it and it seems that the headliner may need to be pulled back to check.
The AC condensate drain hose is 1/2" diameter. The sunroof drain lines are 3/8" diameter. Therefore, the AC line is not a "choke point" as is being alluded (in the prior, now deleted post).
My guess? The hose is not sealing tight against the barbs on the drain pan. With time, and heat, the rubber is likely wearing out. If this is the case then a few zip ties as clamps should suffice.
Even if one of the drain ports were completely clogged the other three should be able to provide adequate drainage to prevent the pan overflowing. It is not like a torrent of water is flowing- just what seeps through the glass seal.
Last edited by ILM-NC G37S; Nov 29, 2024 at 01:15 PM.
Thanks all for the input, real helpful as I’m about to take things apart tomorrow AM
Originally Posted by socketz67
You have eliminated the seal around the door correct? Our cars are 10+ years old, so I suspect that the door seals will start leaking soon due to shrinkage and dry rot.
No, not yet. The door seal appears line, no cracks or discoloration. But I did have my window trim professionally vinyl-wrapped, so maybe the seal wasn’t reinstalled properly. Good tip to check this.
Originally Posted by socketz67
Also, if you pour water into the drain with a small cup, does it exit through the AC drain properly?
Yes, I tested this all when I did the re-routing earlier this year. But I’m now compelled to test again.
Originally Posted by socketz67
How easy is it to get to the top part of the drain near the sunroof as you can't really see it and it seems that the headliner may need to be pulled back to check.
Yeah, not sure on this one. What I’d call the “inlet” to the drain tubes is unclear to me. Both in how to access it and if/how it could cause an in-cabin leak.
Originally Posted by thescreensavers
Best thing is to pull the A pillar and pour water down the drain and see what it's doing.
Exactly, this is my first step tomorrow when I pull things back apart.
Originally Posted by ILM-NC G37S
The AC condensate drain hose is 1/2" diameter. The sunroof drain lines are 3/8" diameter. Therefore, the AC line is not a "choke point" as is being alluded (in the prior, now deleted post).
Yeah, I do have a hard timing imagining how the re-routing could cause a back-up in the drain tubes. I also used a proper 3/8” x 1/2” x 3/8” tee barb to tap into the A/C tube.
Originally Posted by ILM-NC G37S
My guess? The hose is not sealing tight against the barbs on the drain pan. With time, and heat, the rubber is likely wearing out. If this is the case then a few zip ties as clamps should suffice.
Even if one of the drain ports were completely clogged the other three should be able to provide adequate drainage to prevent the pan overflowing. It is not like a torrent of water is flowing- just what seeps through the glass seal.
Drain pan? Hmmm lost me with that term (I assume it’s where the 4 intents are located, around the sunroof).
But I’m def going to check the barb I installed in the A pillar (to join the existing tubing with the new tubing for the re-route). Everything seemed tight and secure, but you never know.
Drain pan? Hmmm lost me with that term (I assume it’s where the 4 intents are located, around the sunroof).
@STownSaint Read through this post as it has pictures of the sunroof assembly. There is a plastic "pan" that surrounds the sunroof glass, or drip tray if you will. As water seeps past the glass seal, water accumulates on the pan which then drains out through each corner barb, down the tube, yadda yadda yadda.....
As only the driver-side is affected, at this point, you should be able to just slightly lower the headliner at the front corner to check things out. Else you will have to remove the headliner to gain full access to the sunroof assembly.
Ok got to taking things apart today, but ran outta time.
TL;DR: I think my front driver drain is totally blocked somehow (near the inlet/within the channel that surrounds the sunroof), which with enough rain, causes water to pool and overflow into the top of the headliner (and subsequently down the drivers A pillar).
Does this theory hold water (pun intended)? If so, anyone have tips on how to resolve??
Evidence as follows:
Exhibit A: inside the A pillar (where I spliced in a new tube for the re-route procedure), all looked fine (note: removed one zip-tie) and don’t think there’s an issue here
Exhibit B when preparing to drop the headliner, I noticed the curtain airbags were still damp
Exhibit C I poured water into the sunroof channel, and the water did not drain down into the A pillar (it did so on the passenger side, and went all the down down thru the passenger footwell)!! I also noticed that the foam between the channel and the headliner was damp !
Exhibit D what I believe is going on to cause the cabin leak (which runs down the A pillar and all the way down to the driver footwell). Could this be possible? Any thoughts on fixes ?.
Exhibit E I tried to check the drain tube’s connection to the inlet, but couldn’t really get close to it. But I also couldn’t see any sign of the tube being loose
Last edited by STownSaint; Nov 30, 2024 at 04:14 PM.
Totally plausible that one port is clogged, though from someone whose roof is open moreso than it is closed, it is rare. Still. Totally feasible.
Being you have the A-pillar trim already removed, just disconnect your spliced connection and run a length of either fishing line or string trimmer line up to the sunroof pan. Any crud should be loosed and allowed to drain down.
Alternatively, some have stated that "compressed air" worked for them
Once the blockage is cleared, I'd rain a small amount of ammonia or bleach to fully clean that junction.
Totally plausible that one port is clogged, though from someone whose roof is open moreso than it is closed, it is rare. Still. Totally feasible.
Being you have the A-pillar trim already removed, just disconnect your spliced connection and run a length of either fishing line or string trimmer line up to the sunroof pan. Any crud should be loosed and allowed to drain down.
Alternatively, some have stated that "compressed air" worked for them
Once the blockage is cleared, I'd rain a small amount of ammonia or bleach to fully clean that junction.
Ah good call, I didn’t have anything on-hand to snake up the drain tube to unblock whatever gunk is up there. But I should be able to get back to it in a few weeks (til then, the car is garaged).
Looks like there are a bunch of pretty cheap pipe cleaning devices out in the market, so I might get something purpose-built since I have time for it to ship
Can you disconnect the old tube from the junction you created and fish something up there while someone is standing at the sunroof drizzling water (smaller piece of tubing or drinking straw would like work)? I do this with the drain in my front yard that likes to clog, albeit its not as fragile. What I'm wondering is if during the course of installing the junction for rerouting, that the hose disconnected from that nipple near the sunroof.
Can you disconnect the old tube from the junction you created and fish something up there while someone is standing at the sunroof drizzling water (smaller piece of tubing or drinking straw would like work)? I do this with the drain in my front yard that likes to clog, albeit it’s not as fragile. What I'm wondering is if during the course of installing the junction for rerouting, that the hose disconnected from that nipple near the sunroof.
It is possible that the tube did disconnect from the inlet, but if that was the case, I would think water would drain right thru (in my case, the water is pooling up in the sunroof drain channel). The tube seemed pretty secure too, although I ran outta time and didn’t get the chance to thoroughly inspect it.
I def need to figure out a way to snake something up and/or down through the orig tubing to dislodge whatever is causing the clog. I’ve got a bunch of smaller control wire on-hand, which I think would be small enough to fit into the tubing, flexible enough to navigate the curve, but rigid enough to break thru what I guess is come dirt and decayed leaves.
We shall see in a few weeks when I’m back with the car, thanks a lot for the tips
