Over the past 6 months I have been in a battle with water penetration into my '06 M45. From searching on this forum and others, it seems like a fairly common problem with different causes. Through various methods I eliminated all other possibilities of water leaks that I had come across: windshield, A/C condenser, sunroof seal, etc. All signs pointed to the drain tubes. Problem was that none of the fixes I tried worked. I tried blowing compressed air in them, I tried running hot water down the tubes, I tried running different kinds of wires down the tubes, etc. I was convinced that my problem was a clog at the end of the drain tubes. Turns out I was right but the reason it took so long to figure it out is that there is no real specific guide or pictures or video online or anything in the service manual regarding drain tubes. I always assumed that the tubes ran from the sunroof, down the A-pillar, and into the engine compartment to the bottom of the car where they are not accessible. Well that is not accurate. The tubes terminate outside the cabin at the front of the dash at the bottom of the windshield. The tubes drain into the same place that water drains from the cowl outside of the car at the base of the windshield. However, I only found this out after my friend suggested just pulling hard on the tubes to see what happens. He correctly reasoned that I was in store for a trip to the dealer whether I ruined the tubes or whether they remained clogged.

So I would love to say that after all my semi-scientific approaches to narrowing down my problem to the drain tubes that I also scientifically discovered where they terminate. But the truth is I just pulled like hell on one and it popped out. So I did the same on the other and it popped out as well. Look at the below pictures to see what we are dealing with in these cars. You'll notice that on the end of the tube there is a black rubber grommet. The tube is somehow very solidly connected to the grommet which is why pulling on the tube turned out to be no problem...again just pure luck. But take notice of the end of the black rubber grommet. You'll notice a little rubber flap that I have to assume is meant to prevent dirt and debris going back up the tube. What this little flap actually does is trap dirt that gets in at the sunroof and runs down the tube (you would be amazed at the amount of water and dirt that gets past the sunroof seal). So my fix was simply to remove the little flap. After 3-4 really strong spring thunderstorms here, I can safely say it's been bone dry in the car.

http://imgur.com/a/Bg0hA

Welcome to the forum and thanks for sharing this!

I'm going to add it to the FAQ thread for posterity. Also, I'm going to post the images in an updated version of your original post for easier viewing.

Thanks again for taking the time and effort to share.

When I removed the A-pillar trim pieces to re-cover my dash, I suspected those plastic tubes were drains for the sun roof. Thank you for confirming that. One would think that based on the size of those tubes, a clog is unlikely. However, now that you discovered that silly flap at the bottom of the tube, I am not at all surprised. That flap is perfectly designed to allow and even promote build-up and once dirt adheres to the flap, the clog is inevitable.
If I were you, I would remove the flap so the water can drain freely instead of clinging to the flap and turning road dirt to a mud plug.
I reckon the dealer would also have found this, but only after a huge expense which you have now spared us all from paying. Thank you !

Hi thanks for your post. A few questions regarding this fix. Given the silling rubber flap, I'm guessing my drain tube is clogged. My dealer quoted me over $600 to fix this by replacing the entire thing, but now I'm wondering if this needs to be done.

1) If all I want to do is try and unclog or remove the rubber flap, can I get adequate access by removing the A-pillar trim. If so, I seem to find some videos online showing you just need to pull hard to remove the plastic fasteners, was that your experience as well?

2) lastly since you removed the rubber flap, have you had any ongoing issues, wondering if the flap was put there to prevent debri/dust in the engine going up into the tube, and if you had any f/u problems since removal?

thank you very much . i am working on the ones that run down the pillars

I have a 2007 Murano that developed an awful moldy smell. By pouring water into the sunroof drain holes, and observing that lack of water exiting behind the front passenger tire, I determined that it was the sunroof drain on the passenger side that was the problem. Water was draining into the wheel well inside the vehicle.

Sealing the sunroof with duct tape solved the water problem, but left the sunroof not usable.

Steps I took to fix the issue:
1) I removed the A-pillar trim on the passenger side using a simple pry tool to expose the flexible plastic tube that drains the sunroof water. Easier than expected.
https://www.dropbox.com/s/1tuyv2vrwdzr0 ... o.jpg?dl=0
2) I took a weed-wacker trim line, and fished it down from the sunroof drain hole. I could see that the orange line made it half-way down the tube, and could see that there was no obvious dirt blocking the tube
3) I removed the trim to the right of the glove box using a pry tool and could see the vent and the plastic drain tube behind it. My hands were too small to reach through it to feel where the plastic tub exited the cabin into the engine compartment, but I could see that is where the water is supposed to drain.
https://www.dropbox.com/s/aglk3yj7gi5xi ... r.jpg?dl=0
4) I opened the hood, and removed the plastic trim under the windshied wipers on the passenger side . I reached my hand to feel where it appeared that the tube should be entering the engine compartment. I felt a rubber edged hole, right where is should have been.
https://www.dropbox.com/s/apwb4c85ab5zo ... -.jpg?dl=0
5) I took my orange trimmer line, and fed it through the hole from the engine compartment into the cabin. Looking through the windshield, I could see the orange line under the dash. It was not feeding up the plastic tube. It was obvious that my drain tube had separated from the drain hole into the engine compartment.
https://www.dropbox.com/s/5dwmwuvmdxenl ... t.jpg?dl=0
6) Returning into the passenger seat, I easily pulled the end of the plastic drain tube from where it entered the dash, and saw that in fact, is was draining water inside the car, since it came away so easily.
7) Using a metal hanger, I was able to retrieve the orange trim line that I had fished in from the engine compartment.
8) I used duct tape to attach the orange trim line to the end of the drain tube, making sure it was attached very securely.
9) I returned to the engine compartment, and pulled the orange line and plastic tube back out from the hole, and into the engine compartment. I felt around to make sure the entire end of the plastic tub was penetrating into the engine compartment.
10) I tied the orange trim line to a solid metal bracket in the engine compartment, since there was no way to remove the duct tape from the tube, just in case it happens again.
11) I poured a cup of water into the sunroof drain, and voila, a pool of water poured out on the ground behind the tire.
12) I immediately took some pics and thanked those responsible for the NICOclub forums!

Overall, this was an easy fix, requiring no special tools. A local mechanic quoted me a few (500) hundred bucks to pull everything apart to diagnose and fix the problem. I was able to fix the problem in less than an hour, with zero mechanic skills.