Water leak into the passenger foot well

GEENAGIRL

MEMBER
2004 BMW 530I
3.0L
6 CYL
2WD
AUTOMATIC
197,000 MILES

Whenever it rains, I have a puddle of water in the rear passenger foot well. The auto shop first told me the vapor barriers we okay, that it was caused by clogged sun roof drains. They said they unclogged them but there was more water after a storm. This time they said it is the vapor barriers, which they re-sealed. Again, the car still leaks. They now claim the need to take the carpets up, not to dry the car, but to see where the leak is coming from. I asked if the drains in the front of the car were checked but cannot get a straight answer. Can those cause a leak into the rear? If in fact, the sun roof and vapor barriers have been repaired, what else could it be? Would I be throwing more money away by lifting the carpet and seats, etc?

1 Reply

STEVE W.

MECHANIC
13,573 POSTS

Well they did the items that are known leaks on those platforms. The sun roof drains can clog and the lines can sometimes fail as well Those are the front lines you mentioned.

The doors are a known leak area, the moisture barrier is even a subject of a TSB about the leaks. Also check the door drains under the bottom of the door, they can get plugged and cause water to get trapped in the door and leak out through the door panel retainers.

Another problem area are the foam door seals. They get crushed down over time and don't seal. When it rains water runs down and gets between them and leaks out onto the floor.

You could take a garden hose or sprayer and spray around just the rear door seam, then check for water inside. Shouldn't take much water to make it damp enough to discover where the leak is. As an aid you could take some baby powder and dust the area around the door between the seals and even dust the seals. Then a gentle spray and look for damp powder.