Hi, I own an '89 Firebird and I have a serious problem..
Rain keeps leaking into the car from underneath the dash.. I've removed the cowl vent cover and there seem to be a lot of holes in the cowl vent underneath the windshield.. The water simply leaks straight into the car onto my floor inside the car.. I know this is real hard to fix but think with me here..

I might have a temporary fix but I need your opinion on this..
Does anyone know if it is possible to cut a flexible tube in half on the lenght and put this tube into the cowl? This way all water coming into the cowl is being catched in this tube and then guided to the sides to drop through the right holes onto the ground. You could put a small block in the middle of the cowl and lay the tube on top of it. This way the water will float away to left or right...
Does this sound like a very stupid idea?

 

it doesn't sound dumb, but I'd be concerned with rust/rot down there causing your problem. If that was the case, it'd be better to fix that instead because A.) it won't leak when done and B.) the hose is just a band-aid, it will still rust and rot even more.

 

wire wheel the rust the best you can on both sides

por 15 the stuff

lightly sand por and fiberglass over the whole area