Water leak in the BMW 530i e39

Details

Parent Category: Hobbies

Published on Tuesday, 21 December 2010 16:33

So Jack and I walked out to the BMW 530i the other day, open the right rear door and then Jack says "whoa Dad, there's water in your car". We had had 3 consecutive days of rain (which is rare in Southern California) and a few inches of it decided to collect in the floor of the car. I thought to myself "how does this happen?" and "this is a nice car". A little research from my wife Kelly discovered that this is a typical problem with the e39. And after a little visual inspection and simple repair on my part, it was obvious that it was a quality control issue at the BMW assembly plant (either the adhesive was poor or the vapor barrier wasn't seated properly - see the pic below).

Learn how I fixed this issue after the jump.

 Thanks to a couple of posts from bimmerforums.com and bmwtips.com, I was able to understand what the problem was and how to fix it. I won't go into too many details here and will instead refer to the original posts. But in short, the leakage happens as a result of water coming in through the crack in the door, where the window slides down. Water then is supposed to deflect off the vapor barrier and exit out two drain plugs in the bottom of the door, then to the outside of the car.

Problems arise when the vapor barrier becomes detached from the door and water then leaks from behind the door panel, down the rocker panel and into the floor of the car. To repair the vapor barrier, but the basic steps are:

1. Remove the door panel. This can easily be done by first removing a small screw (torx screw driver or socket set required) behind the door handle. Next step is to simply pop the panel off the door using a flat head screw driver. Lastly, pop the top of the door panel off the fasteners by pushing it up and out, away from the door.
2. Activate the original adhesive and re-install the vapor barrier. Not every section of the vapor barrier, but a great deal, was completely removed from the door. I read from this post on m5boards.com that someone used a heat gun to heat up the factory adhesive and then simply re-attached the vapor barrier to the door when the adhesive was hot. I didn't have a heat gun but I did have a propane blow torch, so I figured I'd give it a shot. Be careful when using a flame that you don't leave the flame on the vapor barrier or the adhesive too long, otherwise both are likely to melt or catch fire. Other posts suggested using 3M or other water resistant silicone. I used the torch and did a section at a time (see the pics), starting with the bottom of the door (a decision I made because the barrier was still partially attached at the bottom left).
3. Re-attach the door panel

This post is not that instructional. Refer to the links for more details.