Fixing Plymouth Valiant / Dodge Dart water leaks
Like many people, I had a Valiant with an unkillable 318 V-8, TorqueFlite transmission, bench seats, and four doors. It also had the usual Valiant problems, which the dealer could not fix: stalling, defective windshield wipers, and a water leak. All were easily fixed (see other sections on this site).
Water from the air conditioner (second generation)
This one dumps water from the air conditioner onto your (or your passenger's) feet. It can occur even in winter, because the air conditioner is automatically activated when the defroster is used.
The nice thing about this feature is that you can take turns harder than usual if someone you don't like is in the passenger seat.
There is a little black rubber tube that comes out of the bottom of the evaporator and exits through the firewall on the passenger side. It bends at a 90 degree angle, protruding about half an inch into the engine compartment to theoretically let water drain and harmlessly splash onto the ground. (The photo below shows it as views from above; it goes through the firewall at the groove near the right-side end.
Over time, the tube's end can seal itself. The water then makes its way inside the car, and is stored somewhere in there so it can be dumped onto your feet even on dry days. This is, it must be said, far less likely than the metal tube reinforcements rusting out and the tube itself inside the car.
Water from the Valiant air conditioner (first generation)
Nathan J. Nagel wrote: "In my (1967) car, if you pop the hood and look down in between the rear of the hood and the front fender, behind the vertical part of the inner fender, you will see, about 6-8" down, a hole drilled into the side of the cowl, with two little drain things below it. They look like about the top 1/3 of a circle, and the bottom (flat) edge is the flange where the cowl piece welds to the part of the firewall that wraps around to mount the door hinges."
Windshield wiper pivot arm water leaks
The rubber water seals surrounding the windshield wiper pivot shafts may dry-rot enough to let water come through the shaft holes, dribbling down wherever it desires floor. These parts are not available from Chrysler but a replacement kit is advertised in Harden's Muscle Car catalog; it is an inexpensive kit which comes with new gaskets for the inside of the pivot mounts and some caulk strips. The procedure requires the removal of the shafs and arm assemblies which is a bit of work, but it was well worth it! The kit was made by Schumacher Creative Services in Seattle. (This tip from John Cirillo).
Between the hood and the base of the windshield is a little grille (which is also present on most modern cars. This is the cowl. Keep it clean of leaves and other trash. The cowl is used to bring air into your heater and a/c system (HVAC). If the drains are not kept clear, water may sit there and cause rust and worse problems.
Other water leaks
Shakercuda: If it not from the wind shield it is from the dash to cowl side (fire wall to side panel) the only way to find it is just close the car up and stand on your head with a flash light and look for the drips to start. When you find it do not bother with any type of cheap sealer like something from the hardware store. You will need something that will bond with the area you put it in. The dealers have good material for that.