Fred Kiehl

I have been chasing a leak that filled the passenger's side foot well occasionally. I changed the heater core twice, sealed the tray under it, and fixed a small rust hole at the firewall/floor pan joint, when I was replacing the engine/trans. The leak persisted. About the beginning of May, there was a heavy downpour, and the floor was soaked again. I ended up pulling the carpet back, again, and looked for water stains on the bodywork. There were few, but when I pulled the insulator above the carpet back, it wet along about 6 inches of the edge near the A pillar. There is a vertical body seam in the corner of the A pillar and the firewall/floorpan joint. The factory sealant was loose and crumbly. I dug it out, cleaned the area, sanded the rust off, put some rust repair on it, then painted with Rustoleum, and used roof sealant/cement to fill the area where the original sealant was. It took about 2 weeks for another rain storm, but low and behold no water in the passenger's side. It is bone dry.

Just for the record, the drain from the cowl empties just above the area that was leaking on my car. It could be a common reason for passenger side leaks in the 91-92 OCC, and its 91-96 brothers in the Buick, Cadillac, and Chevy lines.

Fred Kiehl

I have found that the leak is still present. It comes from a point near the top of the firewall and the junction of the PS A pillar. I am trying to diagnose exactly where it is. I tried a smoke generator, and it overpowered my door seals, and I had more smoke coming out of the car than I could imagine. I could not see well enough to spot a small leak. I am considering a borescope.

oldcutlass

I hate water leaks, most often it's never simple.

Lady72nRob71

Bummer...
Looks like you should pull back the carpet and camp out in there during the next big frog-strangler, armed with some tools and a good flashlight.
Hope you find it soon!

Fred Kiehl

It has been a while, and I actually found the leak.


I took it to a garage to have them find the leak. They ran water down the windshield and told me I have a leak...great I knew I had a leak. So I took it home and made a small dam from modeling clay with a couple of partitions along the bottom of the passenger's side of the windshield to localize the leaking areas. Well The culprit was in the middle of the passenger's side of the windshield. The center one drained, and the other two held water. I got new water on the inside of the car.


It seems that the last time the windshield was installed (about 2 years ago) the urethane did not stick in that area. I had some widow urethane left over from the rear quarter window installations, and after thoroughly cleaning under the window edge with acetone, I used a thin spatula to paddle the urethane in to about 8 inches on each side of the leak. It has not leaked since then. One more for the home team.

Fred Kiehl

I have an update on leaks. The window started to leak again, and since it had a chip in it, I decided to have it replaced. Well...the whole bottom edge of the urethane was loose. The new install does not leak, but I do not know for how long. At least I know where to look if it starts to leak again.

Lady72nRob71

Wow - this has been a persistent leak! Glad you are making headway on it at least.
I think that urethane is not very flexible, so the flexing of the body could have caused the seal to fail if the surfaces were not cleaned well before application. Hope this next installation will work better!

Fred Kiehl

The installer said that the prior glass was installed over primer, and the primer was chalking. The primer chalking would be the cause of the urethane not sticking to the body.

Fred Kiehl

It has been a while since I updated this, and I believe I have found the final leak.


I did a major engine swap, and in doing so, removed the front sheetmetal. I decided to find my leak. I put a shop vac in the car, plumbed the hose and cord out of a cardboard "vent" window, and turned it on. I sprayed the entire firewall with bubble liquid from the Dollar Store, and waited for the bubbles to show me the leak...alas no bubbles. While I was standing next to the car, I felt a wind on my hand. I looked down, and low and behold, the flexible conduit for the wires between the door and body was only attached at the body end. I surmise that the water was entering the door, or the body, and onto the floor. There has been no rain to speak of since the "fix", so I have not been able to check for a dry floor, but I suspect it will not be wet any more.


BTW, I now have a 30 over 454 in the car, so it is a 461. I still have a few small quirks to wring out, but it does run, and you can see pics on the gmlongroof forum, in the "member projects" section.

Oldsmaniac

Wow what a PITA.... I have a 92 wagon CC and had one prior and both had the same issue with a leak. I found the leak only occurred at speed with the AC on. The fix was to put an elbow on the evap drain tube under the hood. The drain tube is short and sticks straight out. It seems at speed air is forced into the tube causing the condensation from the evaporator not to drain and end up on the passenger floor and also on the rear passenger floor. It was driving me crazy for a while but got it done.

Fred Kiehl

The missing drain tube is a known cause of water on the floor. You can use any tube that has the end facing down or to the rear.


Of course, my other car's heater core developed a leak in the this winter, and I have not had time to swap it out. Well spring/summer is here, and I do not need a heater right now anyway. I will wait until fall to replace it.

Fred Kiehl

I went over the entire front of the car, and it did not leak anywhere. Last summer we had a tropical storm, and it got a lot of water in it, to the point that I took the carpet out, and pressure washed it. I brushed some water color paint around the perimeter of the footwell, and have not had any "runs" in the paint, or water on the floor.


At that time I had a makeshift hood on the car with a hole cut out to clear the taller intake. I believe that, along with a makeshift cover caused extra water to go through the drain channel in front of the HVAC intake, to the point that it flooded into the car. I have since put a better hood on the car, and have not had more water. This may be an ongoing saga the next time we have a torrential rain.

Fred Kiehl

I found a possible leak source. I removed the drip pan under the evap/heater core, and found a crack in it beside the drain. I heat welded the crack, and since have had no water in the car at all (it has rained heavily a couple of times, and I have used the AC continuously). I believe this is the origin of all of my leaks on the floor of the car.


I did cut a little of the heat/sound deadening material out to get the pan back in without re-cracking the pan. I also picked up another one from the local junk yard as a spare for the future.