Nice write up and thanks for the pics. I did the passenger side this past summer as a preventive measure. I may do the driver side later this year.

Again, thanks for the pics!

 

Great job. I actually did something similar around 2 months ago, and it stopped the leak. The only difference, however, is for the driver's side, where instead of drilling a hole I found a small, but open one above the dead pedal, and I extended the firewall's hose past it.

 

Hello, I just bought a 2012 that was literally full of water, did not know that but during inspection I noticed the driver's side carpet was wet, I mentioned this to the seller. He said he will take it to the mechanic and have the drains checked so he did. Mechanic did not find anything wrong with drains and sent him on his way to sell me the car. I took mechanics word for it and bought it. I've been reading forums on this issue for a few days and once I saw what's happening under the carpet I decided to pull mine up and found a lot of water... Both sides had pools of water and everything was soaked. It was an infiniti pool. Even the area in the back had water, where passenger's feet go. I did my best drying the area out with towels then I did the straw mod for the sunroof drains, as this is my primary suspect now. I have not found where it was leaking from just from somewhere behind dash on both sides as firewall insulation was all soaked. I tore out most of the interior except for the center console so I could pull up the carpet on both sides, carpet backing was all soaked, it's like a sponge. I rented a dehumidifier from homedepot, the compact one and I stuck in the car with drains and cables running out of the trunk and in the matter of hours all carpets and insulation were dry, the hardest part to dry was the firewall insulation for some reason. Now, I have a question to the people who re-routed their drains pipes,

• Why drill holes into firewall and floor or tap into a/c line for drainage?
• Did the original drain holes on the firewall not work? Do they somehow get clogged?
• What did you do with those existing holes on the firewall on each side?

For me, it seems logical to use existing outlets instead of making new ones, unless there is a reason why it's absolutely imperative. Have people tried running extended hoses into those holes and call it good?

Thank you

 

The main reason I chose to reroute- and extend- the front sunroof drain tubes was to allow water to flow to and drain from the lowest part of the body in one, uninterrupted path. This prevents water from leaking into the cabin and onto the electronics.

Instead of extending the drain tubes through the firewall and down to the ground, Nissan uses a cheap firewall drain "grommet" to serve as the exit point. The grommet "gasket" has a long history of failure. Through capillary action, water is allowed to drip back and into the cabin. Some have noted that the tube breaks off the grommet fitting as well. Each case is different.

It is extremely difficult to get any access to the drain tube grommets due to the location at the firewall and A-pillar. It would be even harder to route any tubing through without kinking, pinching, or other complications. Possible, yes. Easy, no. For me (and others), it was considerably easier to cut and splice the drain tube from the interior A-pillar and down. I left the firewall grommet as it is. Due to the location outside water will never get in.

FWIW, 3" of rain fell in the past 2 days and, thank God, my Coupe is dry as a bone (though I had to address other leak sources).

You don't mention if your 2012 is a Coupe or sedan as each have additional sources of potential water leaks. Door seals, windshield cowl seals, sunroof.

 

Mine is a 2012 Coupe; and I already modified the grommets with tubes already, I was able to get to them, take them out attach extended tubing to the grommet.

Modded grommets ( I also secured existing hose with zip ties to them)

Drying

Drying

 

Not sure what happened to my first reply, it had photos in it perhaps it wasn't sent out properly or something. As per my original reply, I already took the grommets out and modified them using the straw method. I have a coupe. Accessing the firewall grommets was difficult but not impossible, I simply used plastic trim removal tool to pry it out by grabbing the "tip" of the "nipple". They were rather loose. Then once I aligned them I used extra long 3/8" extension to push it back in place.

 

And therein lies the issue- the grommets do not seal tightly against the firewall like when new. Because water is allowed to just drip from that joint, water seeps back into the cabin.

The straw method is only a jury rigged solution and, in my opinion, the straw is not long or low enough to alleviate water migration. Some have had luck, others not so much. That joint will fail again. I chose to bypass that entirely. Your car, your solution.

As you have a Coupe, pay attention to your door seals- specifically in the area around the mirror/tweeter. These seals are becoming more prone to failure as these cars age. Also, check your cabin filter. If that is wet then you'll have to check your windshield cowl seal.

 

Have you sealed the holes where grommets were? And thank you for the info on other potential failure points.

 

I cut and spliced the drain tube in the A-pillar and routed the tube down, behind the dash, to the floor and out. I left the firewall grommet intact. Due to the location and design, exterior water will never find it's way in through that hole.

 

hey bob, I have some questions about this rerouting you did. If you don’t mind sending me a PM!

 

Anyone have a info on what fittings, clamps and tubing size are needed to do this mod?

 

3/8" ID (Inside Diameter) tubing;
3/8" straight barbed fitting(s);
1/2" x 1/2" x 3/8" t-fitting (if tapping into passenger AC drain hose).

I used zip ties as clamps. These drains are not under pressure so heavy duty clamps are unnecessary, but optional.

 

Thank you so much! I really appreciate it! Last question I had was for the drivers side, someone said they had to drill into the floor, but I see a grommet there or was that added after? Or am I missing something?

This photo specifically.

 

I did have to drill a hole in the floor. I then used a 3/8" 90° ("elbow") barbed fitting (just as you see in the pic). I sealed everything with silicone. Once you pull up the carpet and remove the dead pedal you will see the indentation. Just drill in the center and you'll be fine.

Supposedly there is a existing hole somewhere above where the dead pedal sits that some have chosen to use to pass the tubing through. I chose the floor so that the water will drain straight to the ground and have zero chances of dripping on anything.

All in it cost ≈$25-30 in parts from Lowes except for the T-fitting, I bought that off eBay. It can be done much cheaper but I opted to use stainless steel and brass fittings- just a personal preference.

 

I did see that with routing it above into the opening, but I will drill into the floor to avoid any issues. What would you recommend for silicone to seal the fitting to the floor?

I will get some 3/8" ID EPDM tubing to do the extensions, 1/4" to 1/2" worm clamps and then some 5/16" to 5/8" clamps to secure the cut AC line to the brass T fitting. As for the 90 degree elbow, you just got a dual barbed one?

3/8" ID straight barbs I take just hook up to the existing tube and just zip tie or clamp them?

Thank you again, sorry for all the questions.