If, after a hard rain, your Bimmer takes on water like the Titanic, there's a good place to check: it's called the "Acella Cloth," located behind each door panel. No need to remove the entire panel; just remove your arm rest, door handle and window handle, then carefully pop the plastic buttons that hold the panel to the door frame. A putty knife is an excellent "pry tool." Lie on the ground and look up at the plastic sheet with a flashlight. Check for un-adhered areas that would allow water to run down the door to the sill.
If it needs a re-gluing, use 3M #8001 Weatherstrip Adhesive or any of the "liquid rubber" adhesives on the market. If the Cloth is beyond help, consider removing the door panel and replacing the plastic. Use a shower curtain liner or a heavy-duty plastic drop cloth.
Now, don't think you're immune to this problem if you're driving a late model. Pull up your carpet and check the foam rubber mats underneath.
If your windows fog up for a day or two after the rain, it's a sure sign something's wrong. Just a little more glue in the right spots would have precluded the problem when your baby Bimmer was born!
Author: Stan Simm