Finding/Fixing a leak

[Astro318ti]

I've got a bad water leak on my 318ti. During a recent downpour, I got into my car and found that the foot area of the passenger side was soaked. Maybe a quater inch of standing water. This was less than an hour after the rain started.

Dried it out ASAP, so there are no stains or mildew, but I want the leak stopped, of course.

The enters the passenger compartment right at the base of the pillar supporting the roof. It's right at the corner where the windshield pillar and the dash meet up--there's a little hole between the inside seam and the side of the dash. The water would drip, drip, drip out of that hole--it looks like it's coming from inside the pillar. I've temporarily filled that hole with plastic, but it still means that water is probably seeping somewhere else behind the dash.

I spent this morning trying to find the source of that leak. The obvious place is along the front of the windshield (the plastic piece that goes along the bottom of the windshield is deterorating badly). But after carefully pouring gallons of water along the bad sections, nothing came through the hole. Then I noticed the hole is higher than the bottom of the windshield.

I've also inspected the rubber along the side of the windshield and along the door seam. They look like they're in perfect shape. Again, gallons of water along those seams and no leak.

The final source might be the Cali top. I poured water along the edges of the top. The leak appeared. The only place the seal looks bad is along the front corners and maybe across the front. The rubber has shrunk a mm or so and it looks like water might be able to get between the seal and the body. I can't believe a tiny place like that can lead to that much water getting into the car, but if I can seal it up I can at least eliminate that possibility. No water was getting under the Cali top--water only sat along the seal bewteen the top and the roof.

Could I use something like clearcoat or other liquid to seal that region? Silicone would be overkill--I'd need a bead about the size of a piece of thread.

Has anyone else had similar leaks? Are there any other obvious leak points I might have missed?

[1996 328ti]

This seems to be pretty common, more so in the Fall.
I thought I had bad window seals. I brought the car to the local windshield repair shop. They ran water on the windshield and could see water trickling into the wheel well. The drain was clogged so water was running back up along the firewall. Eventually the water got high enough to come back into the car.

It's hard to describe where the drains are. They look like they along the chassis rails. I'd suggest have someone running water on both sides of the windshield to see where the water is coming through the drain. Hopefully one side is clear and should be able to see water coming out very slowly on the other side. Then just use a flat screw driver to clean out the leaves or debris.

[marcus2116]

i had the same problem but i just adjusted my door latch. my door wasnt closing right

[mickd]

The place I had my windshield replaced this summer on my '95 is a very reputable shop. After the install the tech informed me of a small spot of surface rust that they removed and painted by the lower window seal. He said some shops would not have taken care of it, and there would be a leak there eventually. I'm thinking this might be your problem, you might be best off if you take the car to a good glass shop and have them remove the windshield and check it out, or at least give it a thorough examination. If there is rust at the seal, any other fix without removing the windshield is only temporary.

[96cali]

Originally Posted by Astro318ti

The enters the passenger compartment right at the base of the pillar supporting the roof. It's right at the corner where the windshield pillar and the dash meet up--there's a little hole between the inside seam and the side of the dash. The water would drip, drip, drip out of that hole--it looks like it's coming from inside the pillar.

The final source might be the Cali top. I poured water along the edges of the top. The leak appeared. The only place the seal looks bad is along the front corners and maybe across the front. The rubber has shrunk a mm or so and it looks like water might be able to get between the seal and the body. I can't believe a tiny place like that can lead to that much water getting into the car, but if I can seal it up I can at least eliminate that possibility. No water was getting under the Cali top--water only sat along the seal bewteen the top and the roof.

Could I use something like clearcoat or other liquid to seal that region? Silicone would be overkill--I'd need a bead about the size of a piece of thread.

Has anyone else had similar leaks? Are there any other obvious leak points I might have missed?

Astro- I will bet you six pack you already have found the leak. My cali top leaked at the top of the A pillar down onto the seat and dash (but far less than you described). Were you by chance parked facing downhill? If so all that water is coming toward the small gap at the front seam of your cali top. That may be enough to flood your footwell.

Here is what I recommend:
1. Stop by your dealer and see if your car qualifies to have seal replaced under warranty. They were recalled for shrinkage at the rear center seam.
2. If not, go to the hardware store and get a small tube of clear bath tub silicone sealant (toothpaste size, with small tip attached). Now go lift up the edge of your cali top seal where it meets the paint and start filling. The corner is your most likely culprit. It is not overkill at all and is going to work unlike clearcoat which will crack and flake next to the rubber. This works even better with a real syringe which I think you can get at hobby stores.
3. Check out you drain holes like Steve said. Mine drained out of the black round lift pads under the side skirts.

Email me at ninety6cali@hotmail.com and I'll give you my phone # if needed. Good luck!

[Astro318ti]

Thanks for the replies.

I've looked for drain hole. I did this by pouring water on the other (driver's) side and saw where the water was coming out. Like 96cali, it came out around the skirt edges. So I tried the same on the leaky passenger side, and the drains looked OK. I still did a cleaning, but I didn't get anything substantial out.

I might take 96's advice and try the seal. I'll probably only look for a syringe because the silicone I've used in the past usually leaves a bead about the size of a BB--way too big and really unsightly. I had to do that with my old '82 320i, but that thing was rusted, dented, etc. so a bit of ugly silicone didn't make much difference!

The seal along the back of the cali top looks fine. But you're right--the corners look suspect. What I'm finding is that the water creates a line along the seam between the edge of the canvas and the valley created by the metal of the roof. After a few seconds the level goes down. If it's going down that fast, it could explain the water leak rate.

So I'll head to the hobby store this weekend. I've got a terrible hand for that kind of detail, but I'll practice first.

Thanks again!

[96cali]

Just to be clear, I am recommending lifting up the edge of the rubber seal and squirting the silicone underneath using a syringe so it fills between the metal roof and the seal. The ideal is to have it ooze out just a tiny bit so you know it's filled but there's minimal cleanup. The dried thin film should just ball up off the paint. You are smart to practice and take your time but ideally the work is not visible since it's under the seal.

[Astro318ti]

Just an update.

A couple of weekends ago I took '96's advice and attacked the problem with some Silicone II. Made the tiniest of holes in the tip of the tube and then applied the silicone along the rubber on the Cali roof in the front right corner. Went maybe 4-6" out from the corner both ways. Made a point of coating the area along the outside of the seam where it looked like the leak was occuring. Tested it myself the next day and no leaks.

Clean up was easier than I thought, although I think I left a very thin coating on the paint surrounding the area (just doesn't wipe up well, looks a little "matte" in that area if you look very closely).

Last night was the test. I intentionally left the car out in last night's storm. Woke up at 4 am with it absolutely pouring outside (it was supposed to be a relativley small storm), and it got me worried. Got dressed and moved it back into the garage, but no leaks!

I'll probably do the other three corners as a preventative measure. To prevent any more cleanup problems, I'll mask the paint around the corner.

Thanks for your advice.

[96cali]

glad to know it worked!