Attempting to fix leak after sealing cowl? (pic) [Archive] - Forum


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10-28-2011, 12:20 PM
I have a 95 grand am that has a small leak in the passenger side in the firewall around the computer module behind the padding. It's a very small leak, you can't see a hole like I've seen other people have but it's enough to run back and fill the back seat. Have new carpet ready once I button this up.

No obvious damage under the cowl, I saw a few inches of missing caulking, I used some RTV to seal that up and ran more over the rest of the beads. Just started raining here before I could cover it up - had about 18 hours to set up, though cool here in WI, and it's still leaking.

So the question is, did I miss something in the cowl? The blower seal seems ok. I have some rust convertor/sealer I was planning to use and the glue over the top of it to fix the firewall leak but I'd hoped sealing it above would mean water would no longer even get there anymore - would that be the case? I don't want to plug the firewall hole and have water settle somewhere else and rust through, destroying my new carpet

Picture, leak is coming out at center of the picture, you can see some water following the seam down

10-29-2011, 05:48 PM
I'm not much of an auto-body person, but that area on the upper left looks rusted through. Fix that first. Water can seep through rust and come in that way. Even if the water appears to be coming from somewhere else. It may appear dry and feel cool, but putting something like a paper towel held up to it for a few minutes may reveal otherwise. Probably not what you wanted to hear, but I'm being honest.

Expensive fix (and perhaps the best one): Take car apart to access bad panel, cut it out, weld in new metal. Paint and seal properly to prevent new rust. Put everything back together.

Less expensive (probably not so great unless you get lucky): Clean off or remove what rust you can from where you can get at it, patch it up with that epoxy and fiberglass.

Cheapest fix (likely temporary as it's not fixing the rust problem): Buy that spray-rubber sealer in a can stuff that has been in those TV commercials lately. (That one with the screen door on the bottom of a boat.) Go crazy. Rumor is that stuff actually works to some degree.

If you can afford it, I'd advise to try doing something about the car cancer. It's one of those things that can doom a good runner to a junkyard lot.

10-29-2011, 06:57 PM
Thanks for the reply. I took another look at it this afternoon. I tried putting a small amount of water directly into the little channel below the blower fan with the little factory drain and it's still coming in the car, so I think I probably do have it sealed up, I guess it just normally runs down the firewall to the ground?

I slit the padding where my leak is to see better - looked like you'd have to pull the dash and center stack to get the mat out in one piece otherwise. A bit of rust, though it seems pretty solid still. There is a small, slot-like hole.

I sprayed it with some rust converter. Can't really get in far behind the padding. Thinking about patching it with something I read - some RTV, a piece of cloth, then more RTV on top of it. Maybe I should coat it all, too. Doesn't seem possible to get it from the other side.