Help - 528i leaking water in passenger side

[Todds528ibmw]

Hello,

I'm new here, but thought maybe someone has had this experience.

Everytime it rains, my car gets a musty smell. I finally noticed that the carpet on the front passenger side floor board is very, very wet.

I pulled the carpet up and the foam is soaked. I noticed there is some type of black computer box there mounted to the floor or side (under the sound insulation by the passenger door). I am now afraid that if this gets wet, that the car won't start.

So I jacked up the car to see if there was any damage underneath that would let the water in. I saw no damage, but when I jacked the car up from the side, a bunch of water seemed to pour out from the black flat plastic covering that is underneath the car which covers the floorboards. It seemed to be holding some water.

Would anyone have any idea on how the water is getting in the car and how I would fix this? I don't see any damage and can't figure out how the water is getting in. At first I thought through the door seal, but not real wet there. Could it be coming up from underneath?

Please let me know if you have any ideas or experiences.

Thanks,
Todd

[Teh Prof]

There are channels to deal with water removal, and sometimes those channels get clogged. I would guess that the channels near your cabin air filters, which empty out just behind your front wheels, are clogged. Test it by pouring some water there and watching to see where (or whether) it comes out.

[Todds528ibmw]

Thanks. Hmmm. I thought I saw it wet up top, sort of under the glove box. So your response may be it.

Where exactly would I pour the water? And if it does not come out, how would I clear the channel?

Regards

[Teh Prof]

Open your hood, look at the cabin air filter box on the passenger's side, and you'll see water channels around the filter housing, emptying into a drain hole. This is principally meant for water that comes off of the windscreen. Pour it in any channel and watch as it goes into the drain hole. Your guess is as good as mine on the best way to clear a clogged one, but at least you can sort out what's wrong.

[Todds528ibmw]

Ok thanks again.

I went out and saw the box. In fact, there was a little black rubber tube coming out of the bottom of the filter box that was completely clogged. This has nothing to do with my problem, but I cleaned it out.

Anyway, I will pour a bucket of water over it this weekend and have my wife look to see if it comes in the cabin somehow.

I'll let you know.

[Todds528ibmw]

Found this in the archives - in case helpful to anyone else...

As I have already said above, the problem may be in the sunroof pipes: obstruction in the drainage.

You will not see a rubber hose hanging on BMW unlike other cars the rocker tubes on BMWs are used as drainage lines. If these rocker tubes clog, they fill up and will for sure overflow into either front or back footwells--the parking position of the car will determine this lousy front/back footwells overflow (i.e. uphill vs. downhill). Water (YOU JUST REMINDED ME OF MY CAR I HATE WATER) goes through these tubes which even a relatively light rain can produce standing still water in the car. Older Mercedes has a worse problem with its jacking points (4 Holes on the side of the car where they get so rusty you cannot jack up the car anymore..check the 450SEL in the 70s-80s.

NOW where are they?

You cars should have four small holes ( I mean too small of a hole for drainage--for sure another bad design just like the intake thing) by the front and back of the rocker that allow the water to escape/drain. Look behind the front wheel for the first two and take another look in front of the rear wheel.

As I said these small holes are VERY SMALL and I am very sure these hole do NOT have a job satisfaction for simple REASON: TOO MUCH WATER IN THE ROCKER COMPOUNDED WITH TOO SMALL HOLE PLUS DIRT-- BAD POSITION TO BE IN.

Please note the following three senarios:

Senario 1. Parking your car down hill can be a problem. That is to say: only the front (AGAIN TOO SMALL) holes could be out of commission by dirt and the rocker itself gets filled with water. As such the water (I hate that word) overflows into the footwell before the water level reach the rear drainage holes.

Senario 2. Imagine the opposite parking position where the front is facing uphill ...without going into the above details water will overflow to the back footwell much faster than typing this post---assuming the hole is clogged.

Senario 3. Leveled parking is you best bet of all, this will engage all four holes; but since they are too small to do so and prone to clog by dirt you still have a problem.

SOOOOOO what is the solution?

This is what I did...I used my DEWALT drill with a large bit to make these holes much bigger. Now It will take too much of dirt or too much neglect to clog them; also these poor small holes when they grew bigger by the tender care of my drill! they became more competent in doing their job; that is to drain water. One of these holes gave me a smile of relief.

Warning

DO NOT MAKE THESE HOLES TOO BIG. IF YOU DO, YOU WILL BE INVITING UNPLEASANT NOISE/SOUNDS INTO YOUR CABIN WHILE DRIVING.

ALTERNATIVE: Clean them starting at the roof with the cable TV company wires (coexial Cable) the perfect size and will not hurt anything just tape one end and insert it about 5-6 feet...and YES YOU WILL NOT SEE THE WIRE COMING OUT OF THE OTHER END.....THE WHOLE THING IS TOO SMALL.

If you ask me I will say yes a biological hole whether front or back does a better job in preventing leaks and overflows of all kinds of fluid including acid!!!!!!!

I hope I was of some help to both of you guys; again d3 thanks for your advise you saved me big $$$ on the engine

[npnp]

I have a 2002 525it and I just noticed the carpet on the rear seat on the driver side was soaked. :

[Vards]

My car is a E39, 523, 1997 RH drive. If you take out the passenger side charcoal filter housing (right hand drive model) which is located under the bonnet (hood) you will find an ecu housing. there is a drain plug at the bottom which maybe blocked. The plastic housing which sits under a black lid held in place by 4 bolts is to protect the ecu's. I am just in the process of fixing a problem with water filling up the well on the outside of this plastic housing. It is possible that water can get through to the inside of the car through the loom grommets. Bit of a nightmare to get the housing out, have to dismantle all wiring/ecu/relays etc and unbolt from the inside the car behind glove box. ahhhhhhh. Going to be even worse getting it back together!!!!!

[darkhorse737]

check your windshield seal if any of the above don't provide you ur solution... ;-)