Where is this interior leak coming from?

[C10SLEY]

When it rains, passenger side gets wet down in the corner angle where your right foot would be. Looks like it’s coming from around the heater core on the right side. Any ideas where it’s coming in from on the outside without me tearing everything apart first?

Thanks!

 

[ali_c20]

Test it. Pour water over the Windshield, if it stays dry pour water in the cowl. This way you can find where the leak sits.

 

[Grit dog]

Assuming it’s water and not coolant, my money is on from the seam in the cowl and possibly blocked drain hole in the bottom corner of the cowl.
As said above. When it’s dry, start selectively pouring water to help pin point the leak. Take the valance off the cowl so you can see in there. There’s a transverse seam that I believe tends to be a common leak spot. Or rust through hidden somewhere in the cowl or bottom of windshield frame (under the gasket).
Your truck looks real clean though, so not sure if it has any of the damage I mentioned above. But you didn’t mention how it’s been stored over the years.

 

[gmbellew]

The cowl drains get clogged eventually and water stacks up and comes in the kick panel area. Under the truck behind the front fenders is where they drain. You may have to remove a plastic trim piece and pull some foam out of the way. I've had to clean, flush, clean, flush, etc until I got all the debris out.

 

[C10SLEY]

Thanks for the recs! The truck sat outside, but not under trees, but near them, for 7 years. Since I’ve had it, it’s been in the dry until now. It’s a pretty clean truck with minimal rust (rockers), but I’m believing y’all that it’s a clogged drain and coming in the kick panel area. The vent in the kick panel was caulked around the perimeter before I pulled it out and restored all my trim pieces. I’ve wonder if it was coming from that vent ever since, but the insulation around the heater core under the dash is very wet…. I’ll be checking this tomorrow hopefully. Been sick, so haven’t addressed it yet.

 

[Steelbuddha]

Good to know about the cowl drain holes. I have similar leaks on both sides, despite a new windshield gasket.

 

[AuroraGirl]

There is seals on the hood hinges or should be

 

[CountKrunk]

My truck gets water in through the doors as well with a good rain. The seals are poopy.

Doors will be a whole project themselves someday haha.

 

[MikeB]

On my 82, seam sealer under the cowling was not applied very well at the factory, so it eventually cracked and leaked. In may case, water ran down the drivers side and rusted out part of the fuse panel on its way down to rusting out part of the side panel below the fresh air vent. It's worth a look.