No announcement yet.

Leaking along the fire wall

  • Filter
  • Time
  • Show
Clear All
new posts

  • Leaking along the fire wall

    I have owned 4 e30's and all of them have had a common problem that I never hear any one else talk about. The fresh air door sits under the cowl closer to the passenger side of the car, and I have found that when using a car wash with it open or when parking it south and a heavy rain comes from the west that water runs in the door and out the heater duct on the passenger side of the car. The water pools up on the floor pan and hides there.I have heard of a lot of people having leaks and they really did not know where it was coming from but I have never heard someone else say they noticed this. Alot of the time they think it is the drain that is plugged underneath the cowl but I sometimes wonder if it is not getting in the fresh air door. I guess I was just curious if I am the only one having this problem. I noticed a few posts down that a guy was saying his floor pan had rotted out on the passenger side tunnel right where it leaks out at and it just made me wonder if the fresh air door caused that. I know when you have floor mats it is really hard to detect the leak because the water runs underneath the carpet and pools in the middle of the floor pan. I now pretty much keep my fresh air door closed all the time so I don't forget if I leave the car outside but the amber lite being on all the time is annoying especially at night.

  • #2
    Did you even check that drain that is behind the engine on the passenger side firewall???

    90% of the time that is the was for me...


    • #3
      Yes my leak was definately the fresh air door. As I said, I have owned 4 and have experimented with this alot. All four of them leaked through the fresh air door. That is why I am surprised that I have not heard more about this from any one. Like I said most of the time it is hard to tell that it has leaked because the water runs behind the capet and is usually covered up by the floor mat so the only way you would know is if you checked on it and felt down there. It only will leak under certain conditions, such as a heavy rain from the passebger side or a car wash with high pressure water blowing into the cowl.I sometime's think that the 90% leaking from the clogged drain may not be the only problem and just wanted to let people know that this may be a problem.


      • #4
        Are you sure its not a case of rust on the firewall? I had a similar problem in my old e30. The cowel drain channel often rusts. However, given your description of all 4 cars doing it... thats slightly less likely. Still worth a check though.

        Good luck,
        Chris L.

        Spray paint and tire shine doesn't equate to a "restoration!"


        • #5
          Water only leaks in through the fresh air door when the drain gets clogged. First pull the rubber drain off the firewall behind the engine cylinder head. It will usually be filled with leaves and mud. If your car is old or sits outside a lot, this rubber peice will be hardened and cracked and you will want to replace it. If it is not cloggedm pull the cover off the firewall(a couple of bolt/screws) and reach in there and pull out the dead leaves and other crap that are sitting in there blocking access to the drain I just mentioned. When you take the cover off, you will notice that there is a significant ledge in there that allows water to run out the drain in the firewall. The only way for water to spill over that ledge and leak into the cockpit is when the drain is clogged. BMW would not design a car that allows water to rain into the car through the fresh air vent. Take yours apart and see how it is desgined and you'll understand.


          • #6
            Trust me the drains are not plugged. I have done more then enough work on this problem. They most certainly would design a car that would leak under certain condtions if they weren't aware of it. There are plenty of thing's on these car's that you would think they wouldn't have done but they did. Try taking an instrment cluster out of a car with an air bag and then take one out of a non air bag car. You will see that they did not spend to much time on the redesign of the piece's and they don't work very well with an air bag in place. I am not saying they leak all the time. The fresh air door is not in the middle of the car it is more towards the passenger side of the car. I am not claiming that the cowl is filling up with water and then spilling over into the fresh air door. I know that is not happening. I am saying the water can blow in through the cowl vent under certain condition's and it is sometimes hard to notice.


            • #7
              Here's you solution. Don't run your car through those crappy automatic car washes that eat the paint anyway. buy a house with a garage, and if your car does have to be outside when its pouring from the west only park it north, and if it rains from the east, then you can park it south. By the way, it could also be the sunroof drain vents which drop down the a pillar behind the front speaker and into the inner rocker/frame rail. If it really clogs up, it could back up and fill the front passenger area, really unlikely though, especially to four cars. Try a different car wash or wash it yourself.


              • #8
                Water in Passenger Footwell

                Whenever I make a hard left turn water starts to drip in the passenger footwell.. it is cold water... Could this be a clogged A/C drain? If so, any tips on where this thing is and how to unclog it?

                1987 Hennarot E30 M3