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Standing water in rear passenger floor WTF?

62K views 63 replies 47 participants last post by  X2- VIII 
#1 ·
Ok...so we had this terenchal downpour the other day. Went to take the carpets out of the back seat in my 02 540i Touring and there practically a puddle of water on the floor...it's flipp'n soaked! :cry: Where the hell did this come from. Checked by seals and appear fine. Anyone have this problem before? Thanks!
 
#36 ·
Rough Running/Rear Tire Wear

I own a 2003 BMW 525I and it runs rough for a few minutes at a time causing my check engine light to come on. Also noticed that both rear tires are bald in the middle for both rear tires. Any help with these matters are appreciated!
 
#37 ·
I own a 2003 BMW 525I and it runs rough for a few minutes at a time causing my check engine light to come on. Also noticed that both rear tires are bald in the middle for both rear tires. Any help with these matters are appreciated!
You'll probably get more help if you start a new thread, but before you do that, read the sticky thread "How to search," and then try it out. There's lots of info on this. Oh, and your rear tires are probably over-inflated.
 
#40 ·
Finally got both of my rear doors repaired with the 3M butyl (from a tube) and hoping it works. I have not tested it yet since I am waiting for the carpet to dry out completely. Is there is any good process to remove the slight black spots that were developing on the carpet since I had not noticed that the carpet was wet for quite a few days and it had started to develop mold or mildew when I got to fix the leak.
 
#41 ·
I periodically check the door drain holes. Keep them cleared. I need to check my gas cap filler area for a drain. It pools. Doesn't sound right.
 
#42 ·
Leak could be from more than the vapor barrier

I recently picked up a 2002 525i and have been slowly fixing the issues I've found. Last week after heavy rain both of my rear foot wells were soaked. I found this thread here, purchased some butyl tape at AutoZone and proceeded to make the repairs last night.

On both rear doors, the panels had water damage around the hole for the light...material was very soft and back-side dark and moldy. Prior owner probably let this go for a long time. But on one door, the vapor barrier was completely sealed, so I started looking for other sources.

There are two plastic plugs on the underside of the door. Mine rotated loosely in their sockets. Some were filled with water on back-side. There are also the holes the door panel snaps into. Both are lower than the vapor barrier seal. I'm fairly certain I have water leaking from one or both of these areas.

I sealed the vapor barrier on one side before noticing this, so pulled the caps out the bottom, smothered in silicone rtv and popped back in. On the other side, I used butyl tape from the inside of the door. We'll see which method holds up longer.

No idea how to seal the hole for the panel rivet. Perhaps fabricate a flap that you'd have to install inside the door to direct water flow away from these holes?

For all those folks that said they still had a water leak after resealing the barriers, maybe this is why? These other holes located below the barrier?
 
#43 · (Edited)
I recently picked up a 2002 525i and have been slowly fixing the issues I've found. Last week after heavy rain both of my rear foot wells were soaked. I found this thread here, purchased some butyl tape at AutoZone and proceeded to make the repairs last night.

On both rear doors, the panels had water damage around the hole for the light...material was very soft and back-side dark and moldy. Prior owner probably let this go for a long time. But on one door, the vapor barrier was completely sealed, so I started looking for other sources.

There are two plastic plugs on the underside of the door. Mine rotated loosely in their sockets. Some were filled with water on back-side. There are also the holes the door panel snaps into. Both are lower than the vapor barrier seal. I'm fairly certain I have water leaking from one or both of these areas.

I sealed the vapor barrier on one side before noticing this, so pulled the caps out the bottom, smothered in silicone rtv and popped back in. On the other side, I used butyl tape from the inside of the door. We'll see which method holds up longer.

No idea how to seal the hole for the panel rivet. Perhaps fabricate a flap that you'd have to install inside the door to direct water flow away from these holes?

For all those folks that said they still had a water leak after resealing the barriers, maybe this is why? These other holes located below the barrier?
You'll probably find other nice BMW-designed leaks soon. The rivets for the door panels on our cars are outclassed by the ones on the e46s. Those come with a rubber gasket to ensure a better seal. Also, check the front and rear lower corners of each door for a small slit on the metal edge. That's where water is supposed to drain out from the door, and can be clogged with sundry.

Oh yeah, pop the cabin filter housings (not just the lids) and look down inside the compartments underneath to make sure they're not clogged with leaves and standing water.

Another culprit is the A/C system, which has drains either side of the transmission tunnel that can clog up, forcing condensate to leak into the footwells.

More fun .... the drains on each corner of the moonroof cassette can loosen and leak over the years. Sometimes that water ends up in unusual places.... Easy to fix but requires partial detachment of the headliner.
 
#44 ·
Hi, I've just experienced a similar issue on my 535i (F10) in that I was recently driving in a downpour of rain and have discovered that the right rear floor, behind the drivers seat was soaking wet.

I have taken the car back to BMW & they advised that it's the door panel vapor barrier that's causing the problem. They have ordered a new one from Germany for replacement. Holding thumbs, hope this resolves the problem
 
#46 ·
It is not the amount of water and definitely not the vapor barrier fault. Investigated and experimented with it all today. As once was mentioned in one older post that I cannot find right away, it is the sealing around the divider beteen the moving glass and the rear triangular section. It shrinks with time and and produces massive leak inside the door space. Again, if the drain holes are clean it would not be such a big deal.
However the way this divider is angled, it sends the water right on the water barrier part that has an indent inside the door. Water attacks the barrier in the proximity of the door lock and then works down and then into the footwell. At least this is what I observed on both my doors.

Since I did not have much time to fiddle with this, I used a thick plastic bag from a Lemforder thrust arms, cut it to fit the purpose and installed it inside the door with some duck taping. It looks ugly, but it works - tested it in the car wash already. To put it simply, the plastic isolates the barrier from any water and catches all dripping water and directs it down the door towards the drain holes.

 
#47 ·
It is not the amount of water and definitely not the vapor barrier fault. Investigated and experimented with it all today. As once was mentioned in one older post that I cannot find right away, it is the sealing around the divider beteen the moving glass and the rear triangular section. It shrinks with time and and produces massive leak inside the door space. Again, if the drain holes are clean it would not be such a big deal.
However the way this divider is angled, it sends the water right on the water barrier part that has an indent inside the door. Water attacks the barrier in the proximity of the door lock and then works down and then into the footwell. At least this is what I observed on both my doors.

Since I did not have much time to fiddle with this, I used a thick plastic bag from a Lemforder thrust arms, cut it to fit the purpose and installed it inside the door with some duck taping. It looks ugly, but it works - tested it in the car wash already. To put it simply, the plastic isolates the barrier from any water and catches all dripping water and directs it down the door towards the drain holes.
You possibly misread the post you cannot find. Water is supposed to go through the door and with a new seal you get a nice directed stream. With an old seal more water gets through and it drips all over the place. In the end it's the combination of an old seal, poorly designed directing of water flow, and water vapor sealant that detaches readily with age.
 
#50 · (Edited)
Heat is good, I used a hairdryer, worked great (if I used a torch I would have lit my car up ;) ), and replenished the butyl rubber seal where needed with fresh stuff from the BMW dealer. The BEST TIP I learned on here (and I forget who the genius was) is to use a wall paper seam roller on that vapor barrier, over the butyl rubber seal. The roller allows you to bear down hard and apply pressure on the seal, and since I did that, I have NEVER had a leak since. (knocking wood). Using your thumbs, as I was taught by a BMW tech, is painful and doesn't always work.

Get a strong one, with support on each side of the wheel, not one with support on only one side http://www.amazon.com/gp/product/B0..._m=ATVPDKIKX0DER&pf_rd_r=1SBQX5AKNMV2413C5J1P
 
#52 ·
This is an old thread, so I'll just cross reference to the threads found by typing /vapor barrier f3 in the bestlinks, e.g.,
- Vapor barriers: Sealant for door panel vapor barriers (1) & sizes for the adhesive (1)
 
#55 ·
In going through this thread, something Pleiades said in 2013 I think got glossed over. I have never had my door seals leak in 12 years of owning my E39. But I had a terrible problem for months with water in the driver's side rear seat footwell. Would take days to dry out and then get soaked again after a rain. The problem was the drain under my driver's side cabin air filter was clogged with tree gunk (I live in the woods). The water was filling up this cavity. There is a wiring harness that goes through the firewall right under the brake master cylinder. The cavity was filling up, leaking slowly through the wiring harness, down the drivers footwell to the low spot behind the driver. To see this cavity you have to completely remove the driver's cabin air filter to where you can see your brake master cylinder. Not hard.

I took a hanger and poked the crap out of the 3/8 inch hole in the bottom of the cavity. Now I take the air filter housing off every other year and clean it out. Luckily no rust.
Hope this helps someone.
 
#58 ·
Hello guys hope to solve this. Have a leak on rear passenger floors siliconed window seal its back
Well, then you did not seal it correctly and it is leaking still...what did you seal? You need to seal the foam vapor barrier behind the door panel.
 
#59 ·
pour water down the rear passenger window when closed, see if it appears inside the car. if so its definitely the vapor barrier. there are also drain holes in the bottom of the door that can get clogged, clear them if necessary. underneath your front passenger seat you have a power panel. check it for corrosion/damage after the carpet gets wet.
 
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