PontiacBonnevilleClub.com

Water has been leaking into both front footwells. After removing the carpet and spraying the cowl area with a hose, I saw water leaking down the firewall from under a sound insulation pad on either side of the center floor hump (red arrows in photos). I cleaned the evaporator and ensured that the evaporator case drain was open. I also caulked around the air intake duct under the cowl cover. But I'm still getting water leaking into the passenger footwell at the location marked by the red arrow in the photo. Any other suggestions as to the source of the leak? Would it be worthwhile to remove the dashboard?

I'll bet it's still your HVAC fresh air inlet leaking under the wiper cowl. The crappy location of this can be hard to seal up all the way around the flange. I had a leak in the same location and sealed the flange up good with a very liberal amount of sealant and have had no further leakage. Worth a shot verses pulling the whole dash out.

I had this problem with my '94 SE. It was a leak in the windshield seal. Once the windshield was out, several areas of rust were found, fixed, and windshield was re-sealed. No leaks afterwards.

Dude I had the same problem. I used black gasket sealant along the outside roof where the trim meets the metal.

Ironic that this topic was brought up because just two days ago I discovered water in both footwells of my 97 Trans Sport. I was initially diagnosing why my drivers's power seat stopped working; lost the +12 volts to the seat somehow (probably related to the water). So I jumpered a wire over from the passenger side pwr seat, fixed that issue. Not certain on were the water is comming in though. I had to unbolt the two front seats to do my wire fix, I then lifted up the carpet to look under there and that's when I discovered that water.

I think the water has been coming in for awhile, but it is completely unnoticable unless you actually pick up the carpet.

I know the w-bodies (like my Monte and my wife's Impala) have a fault under the cowl. The original diverter strip falls off and allows rain water to dump in through the fresh air intake. My Monte just got wet carpets because if that. Fix is a new piece from the GM Dealer ($4), took less then 10 minutes to install.
It probably does not apply to a Bonneville, but here's the info:
http://montecarloforum.com/forum/sixth- ... fix-26663/

Also, my '94 Grand Am has a worse problem. A small rust hole through the firewall (water rolls down the cowl and along the back of the strut tower/firewall, beats up the seam sealer and finally works into the car). Mine is one of three Grand Ams that age to do that.... I cleaned the debris away and just filled it with a thick coating of chaulking.