Need ideas from where a leak can originate. For two years in a row now I have lifted the passenger side carpet to find the under padding and floor damp in the passenger foot well. I have to fix the leak before rust happens. This car doesn't get driven in rain. But the fairly new window seals are nearly worthless and water does dribble down the door panel when washing the car.

The fluid doesn't smell like coolant but it does have a bit of a greasy feel, but I think the greasy feel is from the seam sealer. Regardless, I pulled the heater core today and did not see any signs of a leak. No water tracks and nothing but undisturbed dust on every surface of the heater case.

Outside in the engine bay the seam sealer appears solid where the fender meets the firewall. But the seam sealer is starting to fall off around the trans tunnel.

 

Check on it before and after next time you wash it. Greasy feel could just be water picking up stuff as it leaks in. You may have remove all the carpet to see what's happening. Could also remove the heater core completely for the spring/summer and cap off the lines, if that's still in question. If you have t-tops, there is some adjustment there. May also be some adjustment in the windows but will have to remove the door panel to see what's going on there. I can't remember but may be some brushes on brackets towards the top that contact the window.

 

There is a seal on the harness pass-through block on the passenger cowl side panel (kick panel). Mine had developed some surface rust under it, and had been "resealed" with silicone at some point in the past. Might be worth checking.

 

I've talked to several people in the business of car restoration and one owns a 3rd gen too. All three said check the seam inside the cowl where the HVAC grabs fresh air, and make sure the drain hole isn't plugged too. I'll start there and see what happens.

Either way, I think I'll cut across the carpet under the passenger seat so I can easily pull out the front passenger section anytime I want without tearing up the entire freakin' interior. The two forward seat mounts, roll cage, and interior trim should pin it down firm when put back in the car.

 

Could very well be the area above the heater core. A simple trick I did (because my 82 was leaking here many years ago), with the carpet out or pulled back, remove the passenger hush panel and get down and watch with a light. Have a buddy pour a nice tall glass of water right into the cowl screen. That's how I found my leak. There was a rusted hole where water had sat in there because the drains on both ends at the fenders were clogged completely up with years of crud.

 

The pad is definitely damp over the transmission hump. Can't dig any further without taking out the entire damn dash.

I poured water in on passenger side and it only came out the driver side fender.

I wish I had x-ray vision because I'm unfamiliar with everything and don't know what things look like or where the seams are.

 

Taking the whole dash out is a chore. I'd start with removing the cowl screen, wiper motor, wiper transmission (all the linkage inside the cowl) so you can get inside and clean that "trough" out really well and inspect it to see if it's somehow letting water in. You can plug up both fender drains temporarily by stuffing some rags inside on each end to slow water from escaping to see if it forces into the car. If after all of that and it still won't leak from there, I would suspect the windshield next.

 

I take it back. Both drains work fine. I just wasn't pouring enough water in fast enough.

There is nothing to clean out of there. My car has always been very clean. Can any of the seam seals be reached from the outside of the cowl? If not, then I'm not digging in there.

 

Found a couple old pictures when the interior was pulled out. Gives a better idea what is under there.

 

Found it. Water is coming in through the wire harness pass thru on passenger side footwell. I thought that area was fairly immune to water as long as I never drove in rain but I be WRONG! The water draining out of the cowl pours right over that hole and trickles into the interior. And it's not just a little bit of water.... it's a lot of water. Guessing the large volume of water is why the pad is wicking water so high up the firewall. Amazing there is no surface rust yet.

I have about 100 wires passing through that hole from 18 AWG all the way up to 10 AWG. Never had a good solution to seal it up but I guess I better focus on it now. At minimum I could install a hood over the hole for now and that will at least stop the trickle into the interior.

Good call, DynoDave. And kentuckyKITT, you're the man! I followed your advice and found it in minutes. Thanks!

 

It's been so long that I don't remember....

Which way does the potted pass-thru housing snap into the body panel? Push and snap into the hole from the inside of car or outside of car? Other way to ask the question is which side does the gasket go on, inside or outside? I'm thinking it snapped in from the outside (gasket on outside).

 

There's a horseshoe or U shaped clip on the inside, IIRC. Pulls out the top, from a channel in the block on the same 3 sides. The block and harness then pass to the outside. It's all molded of the same plastic, so it all sort of blends together...it doesn't stand out like a CPA clip on an airbag harness or something.

I sealed mine up with this. They had it in stock at AutoZone.



Don't drive in the rain, so I don't know how effective it was. I like to tell myself it was a good answer.

A hood or shield made from a piece of stick on sound deadening would be a great idea. Mind if I steal that?

 

So that's what that thing is! You just solved a 10 year old mystery for me. That thing has been sitting in a box of what-ya-muh-call-its with no identity for quite a long time. But I kept it and now I know what it's for!

 

Yeah, If I found that laying on the floor, I would have had no idea!