Water Getting into Interior

[ChiefRider]

I am getting water in the rear passenger side footwell after a rainstorm. I have recently sealed my pano sunroof with vinyl paint protection film; that appears to have been successful as water was getting in everywhere prior to that, and the film is well intact around the sunroof.

A few years back, I did have the adjacent door panel off, and took great care to ensure the inner panel was well sealed at every point before replacing the door panel. My X5 has no rust, and the water incursion takes place overnight when parked. I will likely go back into the door, but thought I would ask, thanks!

[wpoll]

Originally Posted by ChiefRider

I am getting water in the rear passenger side footwell after a rainstorm. I have recently sealed my pano sunroof with vinyl paint protection film; that appears to have been successful as water was getting in everywhere prior to that, and the film is well intact around the sunroof.

A few years back, I did have the adjacent door panel off, and took great care to ensure the inner panel was well sealed at every point before replacing the door panel. My X5 has no rust, and the water incursion takes place overnight when parked. I will likely go back into the door, but thought I would ask, thanks!

I've had this in the past - turned out to be the vapour barrier. A mechanic had mangled it for some reason (chasing a dead door speaker?) and after I repaired it, never had the issue again.

I should add that even when the vapour barrier was mangled, it only ever leaked if the car was parked on a slope, nose down. Parked nose up, it never leaked. I generally never park nose down now, just in case.

[ChiefRider]

Interesting- I always park nose down. Will try the reverse.

The vapor barrier was perfect when I last was in there- I made sure it was sealed everywhere. After I dry it out in the next few days, I'll park it the other way around!

[Effduration]

Unless you replaced the Butyl a few years ago, bottom of the vapor barrier could certainly have separated from the door since you were last in there.

[Salty B.]

Originally Posted by Effduration

Unless you replaced the Butyl a few years ago, bottom of the vapor barrier could certainly have separated from the door since you were last in there.

Most of these I rescue from the boneyard have separated from the door at the bottom. I always use new butyl rope.

[Russianblue]

Originally Posted by wpoll

I've had this in the past - turned out to be the vapour barrier. A mechanic had mangled it for some reason (chasing a dead door speaker?) and after I repaired it, never had the issue again.

I should add that even when the vapour barrier was mangled, it only ever leaked if the car was parked on a slope, nose down. Parked nose up, it never leaked. I generally never park nose down now, just in case.

as much as I could never ever believe that a simple vapor barrier Leak could cause this big of an issue and I tried over and over to prove against it, that’s what fixed it for me.

I thought my vapor barrier was sealed, but I ended up using some foil tape for HVAC and that solved the problem.


The fact that BMW left the vapor barrier as one of the primary defenses of water intrusion is exceptionally disappointing from an engineering standpoint. But what do you do?

I also shoved a little bit of RTV into the gaps on my window trim seal.