While washing my '70, I found a rather large amount of water had leaked onto the passenger side floor mat. I believe it may have come through the windshield wiper area Has anyone experienced this problem or have suggestions as to where to start looking?

Are you sure it was from washing the car and not your heater core? That's where they leak to. I would check the base of the windshield on that side and make sure everything is tight(molding)

C3s have a leaking problem with the the A pillars ( windshield pillars). Run a stream of water down your windshield pillar and see if you have water on the carpet. If you do the seal between the pillar and your windshield is shot. The windshield will need to be pulled and resealed. If is has been leaking for some time you wiil likley have rusted pillars. If it is surface rust it can be sanded and coated with POR 15. I have seen some that are rusted so bad the pillars need replaced, very costly job. Check your upper cowl area for leak also. Hope this is of some help. Chuck

My 74 always puddles on the passenger side when I wash it, so I am careful not to put a lot of water on the roof. My wife was in the car cleaning it and told me that water was coming in everywhere. I need new roof seals and windshield seal too. Heater core is disconnected because it leaks too. Lots of work ahead of me.

I get a little water in my vette when I wash it too. I think mine may be coming in around the pillar and at the top of the window closest to the rear of the car.

The passenger side glass panel leaks a small amount, but the drivers side doesn't leak a drop. Both of mne fit pretty good, and both are original. I'm not going to worry about a small leak though. I could open a can of worms...

Mine leaks when it's parked nose down. The water runs in the channel around the rear deck lid (convertible lid) and forward (downhill). It then runs down the back vertical part of the door jamb, under the sill cover and into the front wheel well. The drains in the rear deck lid are in the rear. They drain into the rear plenum and straight aft (convertibles) or to the side (coupes). Make sure those aren't clogged either or it'll drain into the rear storage area. There are also often missing firewall carpet grommits - water runs down the firewall and into the car. The other way is the deep abyss on either end of the wiper bay - it should drain out the bottom. These get plugged with leaves and crud - then it flows in over the birdcage (causing body mount issues!) at the bottom of the footwell - behind those fake speaker grilles. (Speakers in dash (2) in 1970). ~Juliet

Another thing to check is the plastic liner in the door, water runs down the outside of the glass and into the bottom of the door, and overflows into the car if the plastic isn't sealed to the door. Also make sure the cover plate for the power window motor is there. Thirdly, there should be a rubber lip at the back of the sill plate to keep water from running into the car that way. Joe

I get water also, mine is from the passenger side window.
Have replaced the seal but still have the problem.

I replaced my t-top seals and it leaks like a huricane after washing. When I pull out of wash station to dry it off I get a soaked crotch. NOT FUNNY !!! Talk about a wasted $300 worth of work and materials. It will never keep me from keeping it clean. So until there is a perfect fix I will continue to enjoy the ride !!!!!!!