Antarctico

While chasing down a Bose speaker problem, I found this mess under the passenger side carpet of my 96 C4. My car lives outside under a stupidly expensive car cover and has been off the road for about 16-months for various repairs. The carpet amd carpet mat were dry as a bone (no antifreeze, this is pure H2O). The carpet padding under the seat is slightly damp, but not wet. Any Guesses as to where the leak might be?



1996 C4 passenger side footwell, totally soaked.

staketruck05

Targa seal perhaps

Antarctico

Since there was no visible water in the car (drips, stains,etc.), and the carpet was dry. I am thinking the water came down the firewall. I checked my three cowl drains and the middle one was clogged with this foul, black goop, but the two outer drains were clear. It's going to rain like hell in my area for the next several days, so I guess I'll find out if clearing the center drain helps. It's like I'm doing science in my driveway. 😆

Red86Z51

Sounds like you nailed the source of your "mystery leak"! You only mentioned the center drain so I'll ask a stupid question: Did you check the other 2 drains in there as well?

Antarctico

I did, they were completely clear.

paul1988

I fixed a similar leak last year.
At first water leaking along the A pillar, hard to tell at first it would just leave a few drop here and there that would dry quite fast. The water would find its way to the bottom without even meeting the carpet.
The other leak was water creeping along the firewall where it meets a plastic part of the HVAC. I put some strip caulking where the car body meet the black plastic and it stopped. However my car was a 1988 so this was probably different?

My complete solution: remove the weatherstripping, remove the weatherstrip holder, remove the windshield molding (see FSM), clean everything and have it bone dry, put RTV sealant, put the windshield molding, put more RTV, put the weatherstrip holder, install the weatherstrip with glue.

Now strip down the whole passenger side footwell (removing isolation and such) and wait for the next rain or hose down the car. See if water still come in and plug it with strip caulking.

paul1988

So that you get a better view, this youtube video pinpoints the leak that I had perfectly :

vette196

I was just about to start a new thread with pics, so I'll jump in this one if I may (I already cleaned out the 3 drain utters). 23 y.o. black goop like the OP said, the passenger side which is difficult to find and I bet never gets cleaned



I saw a line of water running down the black strip and the padding behind it is soaking wet. This is the passenger side and the trans tunnel is on the left

Antarctico

Wow, I watched your video, and that was quite a leak you had! The rain they were calling for in my area never happened, so I am going to do what you did and use my garden hose to see if iI have any other issues besides my one clogged drain. I suspect I probably do, but we'll see.

Antarctico

So, if I'm reading you right, cleaning out the drains did not stop your leak?

vette196

No it didn't, I was really hoping it was the drain utters. The idea of messing with the windshield molding, etc scares me, I hope it is something simple with the firewall

paul1988

Actually that was not my video, but my leak was from the same place.

If you have access to a water hose, try to run in in different places.

vette196

Big rain storms in NJ (what else is new)

I bet she's taking on water, we'll see if it ever stops raining

How about you Anta, raining heavily in MD?

Antarctico

We got hit last night, but today's rain is keeps getting pushed back. Now it's supposed to start around sunset. Maybe all the rain is stuck over New Jersey! 😆

DGXR

Everyone put up pictures of their empty drippy garage floor and we will try to guess what is leaking. LOL

jpipx

Is it possibly coming from the air plenum?

Antarctico

Do you mean air box around the A/C condenser up in the dash? If so, I ran the A/C for about 45-minutes in the driveway today and I got a huge water puddle under the passenger side of the car, but the interior was bone dry, so the A/C condensation drain is open and doing its job.

vette196

Interesting sight this morning....I pulled back my soaking wet (water RESISTANT) car cover and before the rain I put a piece of cardboard between the windshield and the hood covering the cowl (the gap was creating a "pocket" that was pooled with water and I'm sure some seeped into the cowl), the cardboard was wet...

the front of the passenger side (near firewall) is dry BUT I looked where the seat goes and there was a puddle there I think this may be coming from the roof (new weatherstripping). I had to leave for work, so I couldn't dig deeper, yet

The mystery deepens!!

Antarctico

My cover does the same thing. These weather resistant covers lose their water repellancy over time. Still, they were never waterproof, just water resistant.

About your roof, I had just installed (among other things) new sun visors in my Vette, and because I was taking the roof off repeatedly, I neglected to fully tighten the forward roof bolts, so the windshield header gasket was not fully compressed. The roof was on tight, just not cranked down till the forward bolts bottomed out. I don't know if this contributed to my issue.

vette196

I couldn't beat the deal on this cover, but if I had to buy one it would probably be the NOAH cover. I just wonder if it's any better with the rain than the coverking stormproof cover I'm using. I tighten the top down, but I need to check the ws weatherstripping.
I think the front pass. floor issue is related to the cowl. The new one (right below where the seat bottom is) needs to be checkout better as I had to leave for work. I will report back