It's driving me crazy. I have a leak allowing water to accumilate in the passenger side floor pan of my '89 GTU. It is definitly not from underneath the vehicle. Only place I can think of is from the side panel or underneath the dash. Tried hosing the car down but the leak is too slow to see. The car is my daily driver so I am trying to avoild removing the dash until I get a better idea of where the leak is. I can see no holes drilled anywhere so I assume the car came from the factory leaking. Anyone who have had their dash off have any ideas what area it may be coming from?
Thanks.

 

If you can't see a leak when hosing the ca down, it's very possible it's coming from underneath. I had a small rust hole (2 inches long, 1/4 inch wide) in my floor pan that would collect some rainwater during driving and dampen a section of carpet. It was right behind the tire so when water kicked up some of it would find it's way in I cleaned the area with a grinder, got the open sides of the hole very close together with a bit of hammering then welded the area shut. I hit it with the grinder again and sprayed a bit of rubberized undercoating to protect it. Thankfully, everything else under there was mint

I'm sure This was an unknown problem for me for a long long time and the corrosion slowly advanced until enough water came in for me to notice a slightly damp area of carpet.

Check it out...

 

That's what I thought! I have sprayed and caulked underneath like crazy.I dried out the floorpan the day before we got the deluge from hurrcane what's his name. The day after the rain there was water in the floorpan and the car hadn't been driven.

 

Check:

Drain tubes for sun roof.
Door fitment and gasket. Try the paper trick. Place a piece of paper where the door meets the body and close it. You shouldn't be able to slide it or pull it out easily. Do this all around the door.
Windshield. Has it been replaced?

 

What would cause a leak if the windshield have been replaced?

 

Mine leaked through the bottom of the door...if you remove the door panel you will see a big piece of plastic. if the tar like stuff is not sealing all along the bottom, splashing water will collect and drip inside the car...If this happens mainly during hard rains then I suspect this is it!

 

Does it have ac? If it does the stock drain for the evaporator could be plugged.

 

That would be my first guess as well. Mine leaked in the drain tubes in the sunroof and collected on the passenger floor. Water just ran down the side of the door under the dash and on to the floor.

 

The big question is...when does it do this???
Does it do this only when it's raining???
If so, sunroof (do you have a sunroof???) drain hose(s) is clogged or kinked.
I had one kinked in the passenger rear, and the water drips down the side into behind the passenger seat mostly.

Are you using "green" coolant?
It is most likely coolant!
Heater hose on the firewall get corroded and spring a leak.
Unfortunately, it leaks INSIDE rather than outside.
To verify, use a WHITE paper towel or napkin and soak some of the wetness up - is it green???

If not, clogged or bent AC drain hoses (it normally goes through the firewall) will also back up condensation up under the dash.


-Ted