ok,interior is stripped except dash,i have car sitting in driveway and have been checking on the car when it rains and when it does rain i have water trickling down the firewall on the inside of the car.it would appear on the passenger side to be leaking from the insulation around the heater/ac diverter and leaking from the carpet holder?on the drivers side. i assume i need to remove the heater a/c diverter and reinstall it on the passenger side,the drivers side i have not inspected that much however i know there are 3 bolts going through the firewall with nuts on the engine bay side as far as removing the box.i am having touble figuring out how to get to these from the engine bay and could use some help,also is there anything below the hood where it is vented i need to check thats letting water access the inside of the vehicle a 75 model by the way.No my heater core is not leaking.the car is parked not running with no carpet or insulation in it and it only trickles when it rains and on both the driver and passenger side.i have removed the the piece from under the hood below the front window glass that keeps leaves out and have vacuumed the trash(bugs and leaves)from over the years from these areas.thank you for any helpful tips.

 

there should be more than 3 bolts there. I don't understand what you mean about having a hard time getting to them?

 

there should be 3 bolts that go through the firewall into the engine bay and have nuts that have to be removed from the engine bay side,yes there are more bolts on the interior side of the firwall but i am not having any trouble with those but manual says i have to looosen the inner fenderwell to get to one of the nuts on the engine bay side.

 

I get it now. I forget how to do it ina second-gen, but I do remember being able to take out the heater box onthem without removing the fender. I was also able to take out a complete A/C unit without removing the fender

 

ok i got the air box out and took out the kick panels and shut the doors and sprayed the car with water and i believe it is leaking at the kick panels on both sides and that the insulation was soaking it up as well,i looked at both kick panels and they were caulked or whatever thy use to seal them around the opening.so i believe i just need to claen real good and seal them real good.it was not silicone they used from the factory so any ideas on what to use when replacing them?on another note i did have to loosin thefender well to removeair box/diverter and i was surprised that it has no caulking around it, it is only mounted over the firewall insulation.there were no leaks from this area as i did the water test without the airbox in place.