water on my floor.

14pefrank

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I bought my first car (1996 Pontiac grand am se with the 2.4) last fall from my neighbor. she thought the transmission was out so i got it for $250. but it was just low on fluid so i got lucky. the main problem was that the car leaked water on to the floor on the front passenger and drivers side. (caused the airbag to go off in my face, replaced and removed the sensor.) i managed to get the water up and out of the carpet and stopped the leak on the passenger side. i took all the trim off on my windshield and plastidipped and shoegooed the the outside all the way around the window. but after 6 hours sitting in a moderate rain it is moist in the floor. i can't find where its coming from! i even sprayed the car and then looked in it and it was dry then.. my other problem with the car is my transmission fluid disappears. it doesn't burn/leak any. and nothing else is in the fluid either. thank you for any suggestions!
 
Your approach to the leak sounds correct. Go back to the water hose and have someone hit one section at a time while you look for the source. On the trani, place a large piece of cardboard under the car after you have driven it and leave it overnight. Look the next day for drips. I believe your transmission uses a vacuum modulator. If the diaphram inside it develops a leak the trani fluid will be sucked into the engine. Try replacing it if you cant find a leak.
 
Thanks alot for the tips! It sat in the rain all day today and floor is just as wet as it was when I pulled it out of the garage. So i think its just old water coming up from the mat under the carpet. I will check my engine oil for transmission fluid too. What would cause my breaks to loose pressure while driving? I put on new pads and bled the lines, retracted the piston on the caliper, pumped them up and they worked great. But after sitting at school during the day only the back breaks work until I pump them up alot. Then the front and back work.
 
You could check for a firewall hole that lets water in. You have no blockage in the area around where the wiper blades rest in front of the windshield, look at both ends. You probably have ABS and the process is more involved if you got air in the system. Read this link and see if it helps

http://www.aa1car.com/library/abs_bleeding.htm
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I've recently started working on a '94 Grand Am SE, it was my little brothers and now he's selling it. It also leaked water onto the floor whenever it rained, and I finally found the cause. Apparently it's a relatively common problem with these cars. We tried a variety of things while he was still driving it, but nothing ever worked.

I happened to remove the HVAC blower housing because the plastic cover was all busted up, and I happened to have a spare one from a parts car I dismantled a couple years ago. Once I removed that I found the leak, where the water drains from under the cowl through the firewall to the ground, had been rusting out the firewall. Someone had apparently tried to fix it previously by filling it with bathroom caulk from the inside, but that had failed.

I cleared away as much of the rust and old caulk as I could and then went a little crazy with a can of that insulating spray foam, put it inside the hole, and all around the firewall up to the drain and down to the power steering rack. After it cured I used a razor blade and as best as I could, shaved it off flat and at an angle away from the firewall, then cut a small trench in it directly below the drain from the cowl to keep the water from pooling up in any crevices in the foam. Now at no point should water coming from that drain ever touch the metal of the firewall, it should drain freely to the ground, and the hole into the interior of the car is completely sealed up.

So far after washing the car, two rainstorms, and intentionally running water through the drain with a hose, the carpets have stayed completely dry, whereas before after even the lightest rainfall, there would be standing water on the passenger side floor. As for the driver side, this car never had a problem on that side, but there is another drain under the cowl on that side, so potentially it could also rust out the firewall there and drain into the driver side floor. That drain is a little harder to get at though, I think it's kind of near the brake booster and is difficult to reach without removing a lot of stuff. But if that's what it takes to stop the leak, then that's what you have to do.

For good measure, when I reinstalled the cowl (I had removed it earlier when trying to diagnose the leak) I put a nice bead of clear silicone caulk between it and the glass, then trimmed it back with a razor blade after it cured. That way, all the water from the windshield will go through the appropriate holes in the cowl, and no where else. There's an open air box thing behind the blower housing and under the cowl which leads straight to the carpet via the lower heating ducts, so if water were getting under the cowl and dripping into that, it soaks the carpet.

BTW, removing the blower housing is a little bit of a PITA. There's I think 7 nuts/bolts holding it on, but some are hard to reach, and the bottom two were rusted badly. When removing those I snapped the bolts off. With everything back together though it seems to be sealed up tight, despite the two missing on the bottom.

Anyways, sorry for the length, I tend to be thorough, but hopefully the info will help someone else out.
 
thanks for the post
 
have you made sure that it is not coolant leaking from the heater core?
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My 96 se has the leak on the drivers side.
If you take the wiper arms and plastic crowl cover off, you will see a hole in the fire wall that leads into the engine compartment, its a pretty large hole, and on the other side it will have a rubber cover so to let water drain from the crowl area into the engine area.

It will have the factory caulk around the hole inside and out, and over time it cracks allowing water between the two sheets of metal that make up the firewall.
On mine it leaked water for so long it actually rusted and a hole formed on the inside allowing every bit of outside water to leak inside.

I sealed it up with some flexible automotive caulk, and it stopped the leak then i guess it cracked again because its leaking again, but not as bad.

So id check there if i was you, seems like a bad joint from the factory.
 
i took off all of the sealing from the windshield and plastidipped everything that could be covered. on the top i made a half inch wide stripe that rent across the top just to be sure. now i just have to soak up the water from under the carpet. so far it worked for me!
 
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