Water Leak

[Ole87]

So I am in the process of an interior build. I have all of the interior panels off. I had someone outside the truck using a water hose so I could check for leaks around the windshield as I recently had it replaced.

On the passenger side where the panel covers the heater valve, it looked as if there was a waterfall. Water was basically coming in from somewhere under the cowl I assume and running down inside the wall and inside the panel. Its not coming in the truck and getting on the carpet or anything, but again just pouring down inside the frame. Surely it's not supposed to do that? I have pic of the area that I will post this evening.

Any thoughts on where under the cowl it would be coming from or cause?

 

[Ole87]

Here is a pic of the area it is leaking

 

[cblohm350]

I have same issue
mine gets the floor wet

 

[chengny]

That is the RH side fresh air plenum - there is a similar setup over by the parking brake for the driver.

The flap opens to allow fresh air into the cabin without the use of the blower (or passing through the heater core - blend doors tend to leak and allow some heated air to pass). It just flows into the truck as a function of road speed.

The plenums start at either end of the intake cowling that runs across the truck - under the windshield. They drop down past the flaps (the RH side also has an opening that feeds the blower) and terminate at about the level where the door bottom is.

There is, by design, an opening at the very floor of the trunk to allow any entrained rain, car wash, melted snow that comes in with the fresh air to fall to the ground.

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If these get plugged up with rust, leaves, dead mice, etc - the water will rise and eventually spill out of the vent flaps. Poke them out from inside the vestibules with a coat hanger or something

 

[89Suburban]

I concur

 

[jux]

Chengny, you are amazingly helpful!

 

[Ole87]

That is the RH side fresh air plenum - there is a similar setup over by the parking brake for the driver.

The flap opens to allow fresh air into the cabin without the use of the blower (or passing through the heater core - blend doors tend to leak and allow some heated air to pass). It just flows into the truck as a function of road speed.

The plenums start at either end of the intake cowling that runs across the truck - under the windshield. They drop down past the flaps (the RH side also has an opening that feeds the blower) and terminate at about the level where the door bottom is.

There is, by design, an opening at the very floor of the trunk to allow any entrained rain, car wash, melted snow that comes in with the fresh air to fall to the ground.

You must be registered for see images attach

You must be registered for see images attach

If these get plugged up with rust, leaves, dead mice, etc - the water will rise and eventually spill out of the vent flaps. Poke them out from inside the vestibules with a coat hanger or something

That makes sense. I cant say I like or agree with that design which is probably more prevalent than we realize even with our newer vehicles. It allows the truck to rust from the inside out!.

For now as far as I know, it is not clogged as it does drain, it just concerned me of the amount of water that was flowing through there.

As usual, Thanks Chengny for your help!

 

[77 K20]

Old thread, but very good info here. I just found my floor was rusting and found it was from water entering in thru these vent holes. That is a great picture Chengny. I'll be cleaning it out tomorrow while fixing my floor.

 

[MadOgre]

The whole ledge in front of the windshield is like a big gutter. from the windshield to the hood. It runs the entire length of the windshield and drains on both sides down and out where the front fender meets the door.

Sometimes this area fills with debris just like the gutters on your roof and this can cause rusting out if left un cleaned.

I had mine open for access to the wiper actuator arms, and for paint this summer and cleaned it out sprayed with POR 15 rust converter then their marine clean and shot it with clear coat just to keep some protection in there. wasn't really any rust at all, lucky me, but I got rocker panels to deal with so maybe not so lucky.

Its a good idea to clean this area out every couple years and when washing rinse plenty of water over the wiper grill to rinse any salt that may have accumulated through the winter.

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