Water Infiltration - not the air intake

[simanco]

Howdy all,

For way too long now, we've been getting water into the passenger side of the 06 Grand Marquis. Pulled the carpet to let it dry out after the mildew smell got to be too much to drive the car. There was 3/4" water standing under the carpet.

Finally figured out where it's coming into the cabin, after removing the back seat and the layer of foam under it, but have no idea where it's getting past the exterior. See the attached picture.

Water is coming into the cabin through that hole at the underside of the rear door. It will fly out of that hole when you brake, run onto the deck where the seat is supposed to sit, and then pool in the floor.

It's in the space between the panels. I can't see any place it's been running in there. I've pulled out some foam and can see no signs of water inside. I can see nothing anywhere on the exterior of the car. I can see nothing in the wheelwell. The door gaskets appear to be clean and there's no evidence of leaking around any of them. I can't see anything around the rear window.

Any and all ideas are welcome.

Thank you!
Jim

[GM_Guy]

If it is coming out the door, get down and clean out all the drain holes in the bottom of it. There are two or three oval holes, and make sure nothing is lying on the bottom of the insides blocking one of the drains. Dropped screw, anchor, weatherstrip,adhesive,tape,shoelace,pile of mud.

Alex.