Water leaking onto passenger floor during hard rains

Hi y'all. Thought I'd share some troubleshooting of a water leak I had. The leak would only happen during heavy rain storms. This got be a problem living in southern Louisiana. Passenger side floorboard would be soaking wet. Search TW and found the usual suspects (windshield, cabin air intake, roof, rear window) were not the culprit.

In trying to find the leak, I pulled the carpet and glovebox out, and moved the computer out of the way to get access to where I thought the leak was.

Used a pitcher to simulate a heavy rain and was able to narrow down where the leak was. It was coming from the meeting of two body panels. The black line is a plastic straw used in later steps.

Couldn't access the leaking joint through the cowl. So, to get access to the leak from the outside of the truck, I had to remove the passenger side quarter panel/fender. Yes, I know the inside of my fender is particularly dirty...
The sealant between the two panels was beginning to crumble. Where the sealant was really degraded, I was able to pass the straw that comes on a can of brake cleaner through the joint entirely. (Can be seen in the second picture from the inside and the following picture from the outside).
I roughed the metal up from the inside and the outside. Cleaned it with some brake cleaner, and used the pressure from the can of brake cleaner to force out any sealant that was dry-rotted in the seam. Applied gasket material from the inside and outside and forced it into the joint with my tried and trued finger.

Been water tight since. This forum has been great for helping me out with other problems, hope this helps someone else out who may have an unknown water leak.

 

Another one..... Apparently the have no idea how to use seam sealer at the factory. I shudder to think what the dealer or a body shop would charge the unhandy to diagnose and fix these leaks.

 

It looks like we have the following leak sources at least :
Ac drain
Windshield
Cowl to windshield gasket
Air intake curb sealant failure
Clogged cowl drains
Missing bolts on firewall
Leaking rear window
Leaking third brake light
Leaking roof trim to rear window gasket joint
Leaking bolts securing added roof racks
Leaking or missing radio antenna grommet
Back of cab wall seam leaking
Side of fire wall under the fender sealant inadequate or failed (this thread)
Door opening gaskets
Missing or torn plastic under door panels and plugged door bottom drains

Feel free to add the ones I'm sure I've missed and techniques of leak finding.

The guy recently that turned the heater fan on high, shut all the windows and vents and used soapy water bubbles to find his windshield leak was the cleverest one I've seen!!!

 

I occasionally have a few drops of water on the passenger floorboard when I wash my truck, so I may have to do this eventually...

 

Nice find OP. Great write up and with pictures. Thank you for sharing this info. Could you help me understand exactly were the water was running down in? Was it running down the side behind the kick panel? I have this issue aswell. Mine is running down the side behind the kick panel.

 

I found exactly where water is leaking with a borescope/endoscope but getting to it is going to be a issue to get to its at 3 body panel connection ive been working on this for 6months get picks soon. I need s/d card

 

Thanks for this! My 05 is doing this too. How long did the process take?

 

Holy revival! I can't remember for sure, but it isn't very complicated, so likely less than 2 hours.