Rite of Passage... Vapor Barriers are leaking. Contemplating proper design and fix.

[BavarianE31]

Ok, so I thought my barriers were fine, but turns out that the rear driver side door is toast. Ever since I purchased this car one fix leads to another! Guess that allows me to learn more about the 5er. I was getting water between the two lower door gaskets on the door sill but it never reached high enough for it to actually go into the cabin until now. Was under the wrong impression that it was normal to have water on the door sill. Now I know better.

If you have a leaking door, water will drip onto the door sill hidden from view (it doesn't directly do into the cabin yet). There, it gets trapped between the 2 gaskets that surround the sill (the E39 has 3 layers of gaskets for the doors on the bottom) until the reservoir overflows and seeps into the cabin. At least this is what my experience was.

After several minutes (maybe hours) of research there appears to be several opinions as to best fix the issue:

1. Reseal Vapor barrier
2. Seal rear triangular fixed window

The vapor barrier seal is the most common fix. Sealing the rear window may be an option as well (people reported that water only leaked in when water was aimed at this window and the window bar that separates the small one from the main retractable window). I'm going to test this out later today and see the problematic water entry point. Nonetheless, one still has to address the vapor barrier unsticking (for sound and vapor blockage) anyways. Unless you are pressed for time or don't have the means to open up the door.

But I'm not satisfied with the engineering behind it. I'm planning to use Silicone (heard too much bad things about the OEM Butyl tape) and if I need to do the door locks/regulators I'll just cut through the glue (if possible) or the barrier itself and fix it with duct tape afterwards. I don't want to do this again.

I posted a thread about a potential solution here before I bought my E39: http://forums.bimmerforums.com/forum/showthread.php?1952173-Vapor-Barrier-Replacement-Options

But now, I'm planning a simplistic method to get water away from barrier.... Aluminum foil! I plan to place several large pieces of foil inside the door. Tape the bottom edge to the bottom of the door (actually to the inside edge of where the vapor barrier is adhered to), flow the foil down further into the door and then back up (to prevent water from ever touching the tape that holds the foil in place and the sealant that holds the barrier) and then attach the foil to the top; either the barrier or door. Then I'll of course install the vapor barrier right over the whole thing. Two things concern me:

1. The thinness and lightness of the foil means it'll probably get torn to shreds if any wind happens to find itself inside the door. I'll have to tape it against the barrier in several places somehow.
2. There might be noise every time a drop hits it....

I though of leaning a large angled piece of plastic on the bottom of the door to divert water away from the bottom edge but that'll obviously obstruct a lowering window since it has to reach above the point where water first meets the barrier. Not good.

Any thoughts on this?

[cwise12]

I re-sealed mine well with a liberal application of 3M window-weld butyl tape, and put some duct tape over the seam on the outside for an extra layer of protection. It has been almost a year, so far so good.

Try fixing it regularly, and if the problem persists, then get crazy with it?

FWIW, the space inside the door IS supposed to be partially open to the environment. It's normal for water to get inside the door, just not normal for it to make it past the vapor barrier. I would start with the simple fix and see if it solves your problem.

[Qsilver7]

Ditto...some of your theory is incorrect (and has already been explained many times over the past decade)....and my even end up doing more damage.

The fix is to reattach the vapor barrier along the original edges where it was adhered to the door. The water enters the vehicle where the original adhesive fails.

As mentioned by cwise12...water is expected to enter the interior of the door...that's why there are 2 slits at the bottom to allow the water to run out and across the door sill, out to the ground. If you change this, you'll need to somehow find away for water to find its way to the ground, if not, it will be trapped inside the door...which will only increase rust.

Before you possibly & inadvertently cover the drains with aluminum foil...that are built into the design of the door...take a good look for the very narrow slits along the bottom of the door (when it's open) that would be above the sill when the door is closed...you can barely tell they are there...they almost look like a weld/seam...and they are designed that way to keep insects from crawling inside the door or spiders from building webs.

Also, note how the lower section of the doors interior is designed to close just above the upper portion of the seal...this is also where the bottom of the vapor barrier is. When the adhesive fails...and water runs down into the interior of the door...instead of following the path down into th bottom of the door...water will run thru the area where the adhesive has failed (which is on the interior side of the sill)...thus the carpet and foot wells get wet.

Again, the simple fix is to just re-adhere the vapor barrier where the adhesive fails along the bottom sections that would allow water to flow into the interior. Trying to seal up the windows with silicone or adding more stuff inside the door will probably just end up causing other issues.

[BavarianE31]

Yeah, I'm going to skip sealing up the window. But I think I'm going to pursue the aluminum foil route as well as sealing the vapor barrier. I know about the drains and I won't cover them. The idea is to not expose the adhesive to water especially since there's a "pocket" of water that always collects on the seal that never gets drained. Ideally, the foil would be pressed up right against the barrier and flow down past the butyl or silicone glue. It shouldn't interfere with anything.

[agentrnge]

I would not use aluminum foil. I used a sheet of aluminum foil to catch/divert a small slow drip from an under-the-sink water filter unit in my kitchen. The water/minerals corroded the foil in less than a week. I was very surprised at that.

I've replaced/resealed the vapor barrier a few times. Still end up with some water stuck in the door that gets released when I open the door. No water getting into the car. Drains are clear. Its like the shape of the door sill/sill seals holds the water in. Ive pondered cutting slits or holes in the outer most rubber to hopefully help.

[AnotherGeezer]

Gorilla Tape.

[rf900rkw]

The water intrusion is caused by many things, but the vapor barrier is not one of them. If the water is coming in through the door at all (sunroof, HVAC are common), then the basic problem is the water is getting in the door faster than it can get out. The fix is to limit the water ingress and make sure the drains are clear. Sealing up the vapor barrier to be water tight (it was never meant to be) without addressing the real problem just makes the door fill up like a goldfish bowl

Your door is not supposed to slosh when opened.

[cnn]

1+,

Below each door, there are 2 drain holes. Make sure they are not clogged by debris.
In the photo below, I used 2 separate bamboo BBQ skewers to show you the locations of the drain holes...

http://www.bimmerfest.com/forums/attachment.php?attachmentid=322049

[sealbeach740]

Just from personal experience, I tried to add Butyl (3M) tape to the lower area of the vapor barrier first (I could easily see where the vapor barrier had come un-attached to the door frame), and that eventually started leaking again. Next time I pulled the whole vapor barrier off, cleaned off the Butyl tape (off the vapor barrier & the door frame) & re-did it with brand new Butyl.
After it started leaking again, I bought 2 new vapor barriers (1 for each rear door), used black silicone sealer & now it's been good for 2 years.
True, out here in So. Cal., we don't get a lot of rain (& no snow), but I used to get wet rear floor baards after just washing the 540.
Nothing's been wet (not even the door sills), since the new vapor barriers & silicone went in.
And, yes, I'm aware it will be a PITA if I need to remove the vapor barrier again, but i also replaced both door lock actuators at the same time (1 had been giving me occasional grief), and the rear windows don't get used much (I'm usually the only 1 in the car, or maybe a front seat passenger). The rear seats aren't used much at all.....
My $.02.

[rf900rkw]

The bamboo skewers really don't do the drain size justice. You can stick a #2 straight blade screwdriver through them with ease, maybe even a #3. The drains are outside of all seals.

It seems the idea put forth is that the water will leak between the vapor barrier (again there is a clue in it's name) and the door, run out under the plastic door panel, and collect in the sill area. Then, somehow, when the door is opened the water runs up hill and jumps an inch high inner seal to get to the carpeting. Water acting like salmon.... I don't buy it. Besides, the same path can be had by the water running through the door panel grommets and clips.

[BavarianE31]

Drains are clear. I can't imagine anything clogging them up since the gaps in the window seals (for water intake) are pretty small in comparison. Although the vapor barriers were never meant to be water proof, it seems to be the only sure way fix to cure the leaky door barriers. After all of the suffering we E39ers have gone through with these, one would think we figured out the problem; and it points to the VB (all of these have failed in leaking doors). I think water may collect in the cabin and the door sill at the same time when water comes from the door panel gap. It's been pointed out many times that water could flow down the door lock cable and run against the vapor barrier.

I think if BMW designed the barrier better (with a notch like connection only on the bottom edge) then it would cure the problem.

Oh, and good call on the aluminum foil. Never would have crossed my mind. I think I'm going to go with some sort of plastic (polystyrene) that goes above water contact and below the VB seal.

[rf900rkw]

All the trials and tribulations... resealing the vapor barriers time after time using stronger glues and parts from only the finest most expensive dealers. Only to still have water in the floor boards.

I had water in my LR floor once several years ago. I searched and read the forums and found the universal "vapor seal" fix. I then went out and looked at the design of the door. Four words came to mind --- horse shit, can't happen.
Ever notice how most complaints are water in the LR? I did, and wondered why. So I went out to my local friendly BMW wrecking yard and looked at several E39s in various states of interior disassembly. What I saw was the asymmetric design of the rear seat floor vents meant that any water in the evaporator case that didn't drain was going to end up in the :LR foot well. Hmmm.

Cleared out six HVAC drains, and I haven't had any water inside since. Add in the drain in the brake booster well (can it run into the cabin?) and the sun roof drains, and you have many potential places for water ingress. But forumlore says it will always be the vapor barrier.


The cause(s) has been figured out, just not accepted.

[KevinMullins]

I totally agree with ya on the typical drainage issues with the HVAC, sunroof, etc, etc.


I searched and read the forums and found the universal "vapor seal" fix. I then went out and looked at the design of the door. Four words came to mind --- horse shit, can't happen.

But I do disagree about the vapor barrier not being a potential leak problem. The issue is the design of the barrier itself. I haven't had one open in awhile so forgive me for not having specifics, but the protruding areas of the vapor barrier that point inward towards the door catch water as it flows down the window and into the door (usually at the corners) and what happens is that water hugs the barrier and then follows the vapor barrier down to the lower edge, and if not sealed it leaks onto the floor instead of going all the way into the bottom of the door and out the bottom drains. The vapor barrier itself has "design flaws" if you will, it should never have that much water come in contact with it in the first place.

[BavarianE31]

Interesting. I should check all my drains then. Where are they all located?

If I were to pour water on the window you wouldn't expect water to leak into the cabin? Easiest way to tell where it's coming from.

[rf900rkw]

what happens is that water hugs the barrier and then follows the vapor barrier down to the lower edge, and if not sealed it leaks onto the floor instead of going all the way into the bottom of the door and out the bottom drains. The vapor barrier itself has "design flaws" if you will, it should never have that much water come in contact with it in the first place.


This ignores exactly the point I've been trying to make for years now. Water that wicks down the inside of the vapor barrier, if it does, can not "leak onto the floor". Even if that much water came in contact with the back of the barrier, a direct path from the butyl strip to the floor doesn't exist. If the water ran down the vapor barrier, out the bottom, then between the door and the door panel, it would collect in the sill area. From the sill area, it would have to run uphill, then jump over the innermost seal to get to the cabin floor. Ain't happening.

To tell the truth, I've never had the door panel off my car. 14 years old, 175K miles, and nothing in any of the four doors has broken or leaked. From what I've seen, I suspect there is a path the water could take from inside the door to the floor. It has nothing to do with the vapor barrier, and it has NEVER been mentioned in the forums.

[philly98540]

Perhaps street parking can cause enough tilt of car that the sills can drain into the interior? I cleaned mine very good and sealed them to the door with black silicone. No more water after a wash on my sills.

[Qsilver7]

If the water ran down the vapor barrier, out the bottom, then between the door and the door panel, it would collect in the sill area. From the sill area, it would have to run uphill, then jump over the innermost seal to get to the cabin floor. Ain't happening.

To tell the truth, I've never had the door panel off my car. 14 years old, 175K miles, and nothing in any of the four doors has broken or leaked. From what I've seen, I suspect there is a path the water could take from inside the door to the floor. It has nothing to do with the vapor barrier, and it has NEVER been mentioned in the forums.

Perhaps since you've never had the door panel off...that may be why your perspective and comments that appear to refute those of us that have had the door off are at odds.

1. the water intrusion is not swimming upstream like salmon...it enters the car along the area of the door that protrudes over the sill. Next time you're at your car...look at the rear door and notice how the section of the interior door panel above the sill is also on the interior side of the seal. When the adhesive along the bottom of the vapor barrier fails...the water will follow the path of least resistance...which is at the point the barrier fails...which is on the interior side of the sill. The water doesn't flow to the bottom of the door, then fills & overflows into the interior...it goes directly into the interior where the breach in the adhesive occurs...which again, is above and inside the sill.

2. you perception of how much water enters the interior section of the door may be skewed as well. The flocked gasket that runs along the glass (windows) retards the flow of water...but does not stop it. There have been videos made of owners running water over the glass (before) they've resealed the vapor barrier...and the amount of water that can flow into the interior is enough to fill saturate the carpet and footwell.

3. I also agree with you that sometimes a failed sunroof drain can also cause this issue, too.

Watch the videos below as this owner sprays water on the exterior glass...you can see how much water there is that flows down between the gasket and window glass:


http://youtu.be/Ed9IswZOTjo
http://youtu.be/PSrYkslQHIQ

[Aryana]

Interesting. I should check all my drains then. Where are they all located?

+1 Where are these 6 HVAC drains?!?!? Inquiring minds want to know...

[vmbray]

Let me make life a lot easier for you.

Water runs along the vapor barrier and then at the bottom if it is not sealed, will flow between the vapor barrier and sheet metal which means it will be between the door panel and door. It will then merrily run into the car. Period. The design of the rear doors is bad because water dripping from the window scraper hits the vapor barrier and so if the barrier is not tight you will have water in the car.

Best advice I read was not to use window-weld!!! It doesn't stick well to the barrier and you will read plenty of multiple failed attempts using it. Get some black butyl caulk at home depot and use that. Also more good advice is DON'T PEEL THE WHOLE BARRIER OFF and clean it etc. If you have a kid who loves playing with sticky stuff you can pay him to peel it off but even so it's a total waste of time and very aggravating. Also the parts that are stuck will be well-stuck so why fool with them? In fact I finally did not clean the second one (or the fronts which I fixed very quickly just in case) at all. I found that black caulk sticks excellently to the existing goo that had separated and I just re-glued it. It's been almost two years of perfect dry carpets.

I then had a clogged sunroof drain which had a tree nut of some sort stuck in it. Take the A pillar covers off and blow compressed air up toward the sunroof and any crap in there will pop right out the top.

First I've heard of hvac drains but that's good to know!

Good luck!

[rf900rkw]

Q -- Just because I haven't had the panels off my car doesn't mean I haven't had them off other E39s. And I'm very well aware of how much water can flow to where. I spent many years working in a high end Euro shop in the nicer side of town. You would not believe the blockage that can occur from parking on those Crepe Myrtle lined streets.

The constant explanation put forth is the water runs into the sill area and then backwards, up hill, and jumps the seal into the cabin.. This is an accepted truth in these forums, physics be damned. But it isn't going to happen that way. Q is close to the one path I see that makes sense. The water does not run under the door panel, nor through it. The potential path to the interior is through the puddle light.

Got water in the floor board? Don't just rip the door panel off and glue down the bottom of the vapor barrier. Again. Look at the puddle light. If it's wet, the problem is in the door. If it's not, look elsewhere. If it is wet, pull the panel and look for the path. Water likes flowing down, so look up. A common source for problems like this is the wiring to the light acting as a wick/guide.

The six drains. Two in each cabin filter, two under the car near the back of the transmission. And don't forget the one under the booster.

[EricP]

Also interested in finding drains to clean out.. I am going to do my rear vapor barriers and see if that fixes the musty smell after it rains + occasional damp carpet. However I noticed the smell also extends to the trunk! I would really like to eliminate every possible source of water and stank.

[modular93fox]

At the dealer I remove the vapor barrier wit a razor cutting close to the barrier. Once removed I remove all the remaining butyl tape from the sheet metal.. Takes only about a minute or 2. Then lay a bead in the same spot as before. Next I use a torch and hear up the remaining butyl tape on the vapor barrier ... Quick pass' on the barrier as its only foam.. This makes the tape more pliable and sticky. Then line it up and use the roller to make the seal nice and good. It's not rocket science on the barriers.. But if your car is a 99 like mine replace the barriers as I had problems with the butyl tape sticking to the barrier.. And after 2 times re sealing it, I replaced it am haven't had a problem. Why did it not stick? Don't know, don't care because a new barrier fixed it.
Clint

[Qsilver7]

Q -- Just because I haven't had the panels off my car doesn't mean I haven't had them off other E39s. And I'm very well aware of how much water can flow to where. I spent many years working in a high end Euro shop in the nicer side of town. You would not believe the blockage that can occur from parking on those Crepe Myrtle lined streets.

The constant explanation put forth is the water runs into the sill area and then backwards, up hill, and jumps the seal into the cabin.. This is an accepted truth in these forums, physics be damned. But it isn't going to happen that way. Q is close to the one path I see that makes sense. The water does not run under the door panel, nor through it. The potential path to the interior is through the puddle light.

Got water in the floor board? Don't just rip the door panel off and glue down the bottom of the vapor barrier. Again. Look at the puddle light. If it's wet, the problem is in the door. If it's not, look elsewhere. If it is wet, pull the panel and look for the path. Water likes flowing down, so look up. A common source for problems like this is the wiring to the light acting as a wick/guide.

The six drains. Two in each cabin filter, two under the car near the back of the transmission. And don't forget the one under the booster.

:thumbup: