Carpet is soaking wet behind the passenger seat

[unklbenz]

My friend was sitting in the back seat behind the passenger seat and she noticed the floor mats and carpet underneath is totally soaked. Im guessing its coming from underneath the car, any thoughts on this?

[crdiscoverer]

My friend was sitting in the back seat behind the passenger seat and she noticed the floor mats and carpet underneath is totally soaked. Im guessing its coming from underneath the car, any thoughts on this?

No, it's not coming from under the car, it's entering through the rear doors. Search as there are many threads with the solution to this.

Sigh...

http://forums.bimmerforums.com/forum....php?t=1309528

[AnotherGeezer]

It's the optional BMW goldfish pond. Not everyone has one.

[unklbenz]

No, it's not coming from under the car, it's entering through the rear doors. Search as there are many threads with the solution to this.

Sigh...

http://forums.bimmerforums.com/forum....php?t=1309528

Great thread thanks !

[FlipredE36]

Happening to me too. Vapor barrier is most likely the culprit.

[HeathRJ]

Most likely your vapor barriers inside the door. An easy fix:

http://www.louv.tv/cars/m5/leakydoor/leakydoor.html

http://forums.bimmerforums.com/forum...=vapor+barrier

[34BenP]

I have replaced both rear vapor door seals due to water leaking in rear passenger seat footwells. I checked both front doors and the vapor barriers are in tact, no leaks there. I thought the water was being "wicked" through the car to the front driver footwell, since I park facing downhill. I have left the car parked for four days while it has rained every day after having the rear door vapor barries replaced and was surprised to see wet driver footwell...the rear foot wells are both dry. It seems the water is entering under the dash on the driver side. The carpet is moist along the back carpeted wall and gets more wet in the corner where the wall meets the floor. Does anybody have any ideas where the water is entering?

[KPAKEH]

I have replaced both rear vapor door seals due to water leaking in rear passenger seat footwells. I checked both front doors and the vapor barriers are in tact, no leaks there. I thought the water was being "wicked" through the car to the front driver footwell, since I park facing downhill. I have left the car parked for four days while it has rained every day after having the rear door vapor barries replaced and was surprised to see wet driver footwell...the rear foot wells are both dry. It seems the water is entering under the dash on the driver side. The carpet is moist along the back carpeted wall and gets more wet in the corner where the wall meets the floor. Does anybody have any ideas where the water is entering?

I had the same problem with one VW-Passat this summer. It turned out that the problem was clogged with leaves and dirt drainage holes. So when it was raining the water was entering under the hood and then somehow through the ac right in the drivers footwell.
Hope this is the reason for your problem cause there is easy solution - a good car wash.

[pleiades]

Several possibilities....

This happened to me: If your car has a sunroof/moonroof, rainwater could be leaking from the drain tube that's attached to the front-left corner of the sunroof cassette. Can't be sure unless you drop that corner of the headliner, but if the headliner is not wet anywhere, this probably is -not- the issue.

Other is as mentioned in post above. The brake reservoir/brake booster compartment hidden underneath the driver-side cabin air filter housing sometimes gets clogged with leaves/debris and flooded with water. This -might- leak into the cabin floor. You can check by removing the cabin air filter housing. There's a small nickel-size hole down right beneath the brake booster. Clogged or not?

[34BenP]

The problem is exactly this "If your car has a sunroof/moonroof, rainwater could be leaking from the drain tube that's attached to the front-left corner of the sunroof cassette. Can't be sure unless you drop that corner of the headliner." We dropped the headliner and confirmed the dripping water is coming from the cassette in the left front sunroof. I am looking to patch the cassette with an epoxy or silicone. Any recommendations for patching with an epoxy vs silicone? I looked into replacing the cassette and it is much more involved/costly option and the parts are 900 bucks plus a few hours of labor.

[pleiades]

I suppose there must be quite a few choices for waterproofing sealant.

In my case, both front corners were leaking. I made sure the drain pipes were not clogged and then reattached them to the drain nipples on the moonroof cassette using Permatex Ultra Black RTV as an adhesive (making sure not to get any in each drainhole itself). Whatever you use, be careful not to get any on the cabin side of the headliner.

One observation: on my car the rubber connector for each dran tube flares out and has two "ears" that I used to pull it off. It slips on the cassette corner drainhole nipple quite easily but I'm not sure what it would be like new. I might have been better off had I ordered replacements first but I was just sick of the soggy floormats and did the above.

So far, car is dry inside despite sitting out in several heavy all-night downpours.

edit... Forgot to say, if your car has the head-protection tubes up there behind the A pillars, be sure to disconnect the negative cable on your battery when working around in there. My battle was detailed in this thread on another forum.

[34BenP]

It sounds like my shop is recommending using an epoxy, but it sounds like your solution is a silicone based adhesive. I've also heard others talking about a silicone based solution. I was just wondering if silicone would work better.

[AmazizingE39]

It's the optional BMW goldfish pond. Not everyone has one.

[34BenP]

Yeah, hopefully the adhesive my shop uses will hold. Seattle gets a lot of rain, and it's no fun having standing water in the driver footwell. Other than the water leak, I have been very happy with the car. Looking forward to picking it up this afternoon.