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Lower firewall water leak ideas?

eodcoduto

eodcoduto

We could have been closer.
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Water is getting into the passenger floorboard and I don’t know where it could be coming from. I resealed the cowl seam last summer and it stopped the leaks on the driverside, so I’m assuming I got the pass side as well.
In the pictures you can see the lower seam sealer lifted and its coming in from the heater box seam as well. Where else should I be looking for the entrance point, and pulling the windshield isn’t an option right now since this is my daily driver.

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I dug all of that out last year and resealed it with Silkaflex 221. It is hard to get all the way to the edges so I’ll pull the cowl and see, and give it a water hose test.
 
I had the same symptom. Water was also running down the kick panel. I pulled the vent, new seals etc, still had water. Pulled back the carpet, also had water coming down behind the glovebox. Checked the cowl etc.

Turned out Windshield was leaking at the bottom corner. Water was coming in between the gasket and the glass running down behind the dash.
 
That sounds like mine, I may have to call and get a windshield quote to see if its rusted there.
Mine is sand blasted and wiper scratched anyway.
 
Windshield is easy in a square. At least to to pull and inspect for rust.
Not hard to put back either.
I used this on the burbs rear quarter windows Barrier Bond Black Seam Sealer Compound - 10.1 fl. Ounce Tube https://a.co/d/8vwg6A5
 
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There’s only so many places the water can come from In that area. Windshield gasket, air box, or cab seam seal.

Pull the glove box, stick your head up under the dash so you can see on top of the air box. If you can see water damage on the jute over top of the box, you can likely assume it’s not from the box and from the windshield gasket or cab seam. Also, do a water test starting at the top of the air box, then go from there, cowl, windshield, etc.

Coincidentally, I just chased down a water leak in my cab that came from exactly the same spot as yours. It ended up being from the air box. Fun job pulling everything just to be able to seal up the box on the engine side of the firewall.
 
Its not the heater core, it only happens when it rains hard and is just water. The sealer in the firewall side of the A/C box is cracked so that needs done anyway. I had the dash out last month to put a dash cap on and didn’t notice anything but I also wasn’t looking, it will get it fixed, I want new carpet but not before this leak is found.
 
Do you have working A/C? Was down in the south once w/ the A/C running and the condensate was running back into the car. Had an inch of water on the floorboard after a couple of hours.
 
eodcoduto said:
Its not the heater core, it only happens when it rains hard and is just water. The sealer in the firewall side of the A/C box is cracked so that needs done anyway. I had the dash out last month to put a dash cap on and didn’t notice anything but I also wasn’t looking, it will get it fixed, I want new carpet but not before this leak is found.
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There is a possibility for rain water to intrude into the air box after running down the firewall. I assume you know that was being referred to and of course not referring to coolant leaking from the heater core.

The reason I mention this is bc it sounds like you’re aware there is cracking between the air box and firewall. Water shouldn’t come down the inside of the firewall in significant quantities but if the cowl/hood seal is bad, or there is a large gap. Or as was the case in my truck, parked facing downhill with a cowl hood, then water can migrate down the engine side of the firewall and end up on top of the air box. If you have a/c then the water can pool up near the heater hose-air box penetrations and leak from or near there.

Most people seem to have either windshield gaskets leaking or seam sealer that’s bad. Like mentioned either pull the glove box and stick your head around or pull the dash so you can see the bottom of the windshield gasket.

Water leaks can be frustrating, especially from that area of the truck. I’m sure you’ll figure it out.
 
That makes sense, I’m going to put the hose on it in strategic spots and see if I can sit inside and track the leak. It is frustrating.
 
Rains like hell and you get water on the firewall...Cowl is easiest path for water to go through.

Look for plugged vents on the ac/heater box,, openings on the bottom of the cowl get plugged.

The OEM foam sealer( open cell) is notoriously poor.

PIA... Pull windshield wiper & cowl panel for inspection+ recoat all seams....

??? Is the windshield gasket tight to the body
 
eodcoduto said:
Water is getting into the passenger floorboard and I don’t know where it could be coming from. I resealed the cowl seam last summer and it stopped the leaks on the driverside, so I’m assuming I got the pass side as well.
In the pictures you can see the lower seam sealer lifted and its coming in from the heater box seam as well. Where else should I be looking for the entrance point, and pulling the windshield isn’t an option right now since this is my daily driver.

View attachment 469277

View attachment 469278

View attachment 469279
Click to expand...
Is it possible the heater core is leaking ?
 
JT88K5 said:
I had the same symptom. Water was also running down the kick panel. I pulled the vent, new seals etc, still had water. Pulled back the carpet, also had water coming down behind the glovebox. Checked the cowl etc.

Turned out Windshield was leaking at the bottom corner. Water was coming in between the gasket and the glass running down behind the dash.
Click to expand...
Pretty sure that's my issue also.
 
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