Battling a water leak on the driver's side.
 

I've been battling an interior water leak on my front driver's side since winter. I thought it was fixed a while back but unfortunately it showed up again.

I've had two different body shops on four separate occasions take a look at it, in addition to taking a whack at it myself.

So far we've done the following:

• Ran water over every part while carpet, styrofoam, and sound deadening material was removed - no luck tracing the leak.
• Checked door seals and they are fine.
• Checked the body and no rust or holes anywhere.
• Checked any holes in the firewall and everything appeared to be sealed - no water coming from any of the holes/grommets.
• Sealed clutch pedal bolt but that was a weak attempt.
• Checked sunroof and drain tubes, including where the tube exits down low - everything looked fine and water drained as it should.
• Checked windshield and cowl - replaced windshield but it wasn't the culprit.
• Today they removed more material and had it up in the air, using soap to pinpoint the leak, but still no luck.

I'm going to take another whack at it this weekend, but the whole situation has been a hassle with rarely being able to drive my car the past month. Throwing $1500 at it without finding the leak has got me stressed. Do I keep fighting this battle or what?

Anything aftermarket done to it wiring wise? Stereo or air ride suspension?

I think the previous owner had subs in it. I let he body shops know this too but they said everything was sealed properly.

Check the firewall grommet. Either it’s not seated properly on the drivers side or the previous owner cut the middle portion out to run some wires.

The G usually leaks for two reasons: the grommets at the firewall for the sun roof drains dry and crack or the seal at the bottom of the window fails allowing water in through the door.

I was almost certain it was this but the body shop said it was sealed properly. I will check it again this weekend to be doubly sure.

From what I've read on various forums, these do seem to be the main culprits. I've had both body shops check the sunroof drain tubes and both said everything looked in order. I pressed the last body shop to actually check the grommet and run water tests while everything was exposed - they said everything was draining properly and no water was coming in through the grommet.

I don't think it's the door seals though. When the last body shop had everything exposed, they let me take a look and I could see the initial trickle coming from somewhere towards the engine bay. I guess it could be doing some weird routing and such, but it doesn't seem likely.

I will check these suggestions again this weekend, but I'm not sure what to do if I'm not able to find the leak myself. Take it to another body shop? Drill a hole in the floor? Sell it?

This problem is near and dear to me (although it was the passenger side in my case). I couldn't make the sunroof grommets fail in a number of water tests but they certainly were. Every time it rained. Don't understand the physics but it may be a combination of the angle the car is sitting, sheer volume of the torrential downpours here in the NW, or vibrations while in motion/running that compromises the fragile seal. The fix I found on YouTube and wrote about here costs pennies and has been flawless for a little over a year so far.
One comment from that thread that could definitively prove the source that I thought was pretty nifty was someone plugged off the suspected drain tube from the top (with a foam earplug maybe?) and it eliminated their leak. This would seam a temporary fix/diagnostic option but it may just as easily be a permanent option if it worked and you were comfortable with it.

That's a great idea. I will do this then spray the car down and see what I find. At this point I'm willing to try anything as I really don't want to sell it.

My issue was the firewall. I had a sub installed and that was the cause.
It drove me crazy..

Sorry you had to deal with this; it's about the most maddening experience I've had with a car. So was it just a grommet or boot that hadn't been resealed after installing the sub?

UPDATE: I picked my car up yesterday and the body shop said they had left the car out the previous night since a storm was coming. They wanted to do one last check before they put the rest of the trim pieces back. When he checked the next morning, he found no moisture whatsoever in the car and was saying it might be some sort of Christmas miracle. He still wasn't confident it was fixed but said the removal and reinstall of the fender and interior bits might have reseated something correctly.

Last night we had a decent two hour storm - the type of storm that would make my car leak in the past. When checking this morning, I could find no moisture anywhere inside. Color me perplexed.

Is it fixed now? I dunno, not getting my hopes up. But if it is, apologies to anyone that runs across this post in the future, because I cannot pinpoint what fixed the leak. Still going to test it this weekend to make sure.

The same thing happened to my car but on the passenger side. Checked the firewall grommet and the sunroof drain and everything was fine. Tried pressure washing the car and no leaks at all. I'm still confused about what caused it. The only thing that might've triggered the leak was the night before when my friends were messing with the windows and maybe I didn't put it up all the way?

That's odd. I would think there'd be moisture somewhere along the interior side of the door. So did it just leak that one time?

This weekend I sprayed my car down for an hour straight, hitting each angle. I even popped the hood and sprayed water directly into the brake cylinder compartment - the area I believe the water was coming from. No leaks. We also had a good storm last night and my floorboards are still dry. :BOUNCE:

I noticed the body shop put sealant around the parts they removed and reinstalled, so maybe that did the trick. Here's a list of what the body shop did:

https://cimg7.ibsrv.net/gimg/www.myg...c612afe992.jpg

I don't wanna jinx myself, but I think it's almost safe to say my car DOES NOT leak anymore. It only took 4 months of stress, $1500, and an assload of wet vacuuming, but the beast appears to be slain.

****. We had some severe storms throughout the night.....and my floorboard was wet. Plugged the sunroof and still no luck.

I'm stopping by the bank today to get finances sorted for selling it. If anyone wants to buy a mint 2010 G37S 6 speed 60k miles for $13k, PM me. I'm knocking a couple grand off because of the water leak.

There's a Gs for Sale subforum in the Classifieds.

I thought that too but it was the only reasonable explanation in my mind because I did hear the window move up and seal the day I discovered the leak. That was the only time it leaked but I haven't left it in a rainstorm afterward that. Sucks to hear that the issue persists. Good luck with your plans for the car.