Water leak problem

[fleastang]

After a weekend of heavy rain I have noticed alot of water has leaked on the passenger side (more than a quart!). It appears to come from under the dash on the upper right hand side. I removed the cowl cover which doesn't reveal alot on that side but nothing was plugged. I have not driven it so it wasn't condensate from the A/C. I noticed a drip at an interior body panel seam and silicone caulked that but when the A/C was on yesterday I had water dripping in the floor so maybe it is a combo rain and A/C leak. Any help on where this may be coming from would be GREATLY appreciated.

[mschn99]

if its not coolant (heater core) then odds are you need to start checking your windshield for a leak.....

[fleastang]

Is the windshield a common issue on these trucks? Just curious if I am the only one experiencing this or just one of many. I am attaching a TSB I found on the web; have you ever seen this?

TSB
04-23-9 • WATER LEAK - ROOF FLANGE AREA - WATER ACCUMULATION IN HEADLINER AND/OR LEAK AT THE CAB FLOOR PAN AREA
Publication Date: November 17, 2004

FORD: 1999-2005 F-Super Duty
2004-2005 F-650, F-750
ISSUE:
Some 2004-2005 F-650/750 and 1999-2005 F-Super Duty vehicles may exhibit water entry into the cab through the roof to roof flange seam, at the A-pillars. Customer may describe as water accumulating in the headliner, floor pan or bulkhead area.
ACTION:
The leak may be verified by running water (sheeting the water) over the left and right side roof rail area. If a water leak is identified refer to the following Service Procedure.
NOTE: PERFORM THE PROCEDURE ON BOTH THE DRIVER AND PASSENGER SIDES OF THE VEHICLE.

[SuperDuty1]

I had about the same problem 6 months ago. Except after a heavy rain the water would run down the driver side under the dash like it was coming from the windsheild. It turned out to be the seal around the thrid break light on the cab. I replaced the whole light and seal, I think for about $70 from Ford. I havn't had a leak since. Yours might be the same.

[fleastang]

Thanks Superduty1; curious how much water you were seeing with that leak. I took out my 3rd brake light last night and noticed the top of it was not sealing at all. The gasket was detiorated and dirty on the top and not even up against the cab where it is supposed to seal. I am going to replace it today but was just wondering how much water I would see from that. Thanks again!

[samiam]

my truck is at a body shop today having the rear leak addressed. i am experiencing water accumulating on both sides of the rear wall in the crew cab. the source seems to be the body seam running up each side of the rear of the cab up underneath the rear window gasket. it appears a previous owner of the truck may have let something large and flat (camper? or cargo?) bump the back window evenly across, damaging the body seams at the top. for $100 the body shop is putting a new window gasket in it, and shooting some body seam material on those seams. i'm hopeful. separately, when i approached my truck in the parking lot the other day i noticed a drip below the passenger front area. it appeared to be fresh clean water. it wasn't entering inside the truck, but it was coming from somewhere above the rear or the passenger front wheel well. estimate a cup of fresh looking water had poured out. maybe captured somewhere in the engine compartment or fender well following rain a few days before? i sympathize with your situation. water leaks are so dang frustrating.
UPDATE: the shop ended up squirting body seam sealant up on the body seam on both sides of the rear window. the glass company wasn't able to deliver the right rear window seal in time, so they didn't remove the rear window which limited the amount of body seam sealant and the quality of repair they could do. still, it fixed the window leaks immediately for about 6 months. now one side is beginning to leak again. i need to have the rear window pulled and do a quality repair of the body seam and make sure it's not leaking due to rusting out of the window flange.