Getting inside the cowl

[Doppleganger]

Seen alot of how-to's here with the idea of cleaning and sealing the inside leak-prone areas of the cowl. A pig in a poke with whatever sealer you use. So I'm about at that point and was wondering.....when someone says "open up the cowl" - exactly what are they referring to? Cutting the grill off and re-welding it? (not happening) My cowl is 100% cleared and raw steel - needs sealed up. I can stick the paint gun down in between the grids but thats going to make a mess. Cant see a seam sealer caulk tube fitting very well either.

Just wondered what the secret is to getting in there and seam sealing/painting/whatever the whole thing?

Thanks fellas.

 

[pinballlarry1]

Cowl area cleanout, are these fasteners the original correct ones FINISHED!!

Working on the '81 C10, removed the cowl between the hood and windshield. Pretty simple, even taking off the wiper arms went well. Found 3 wasp nests inside up under the space by the windshield. I get several in the door hinge area every year. Cleaned out the usual dirt, debris, leaves and...

www.gmsquarebody.com

Here's what I did over the course of 3 days with no rain. Easier to do than I initially thought.

 

[TotalyHucked]

What do you mean cutting off the grill? It unbolts/unscrews. Then there's large holes that you can get into with your arms and a paint brush/caulk tube, whatever you prefer to do to seam seal it.

 

[Doppleganger]

Cowl area cleanout, are these fasteners the original correct ones FINISHED!!

Working on the '81 C10, removed the cowl between the hood and windshield. Pretty simple, even taking off the wiper arms went well. Found 3 wasp nests inside up under the space by the windshield. I get several in the door hinge area every year. Cleaned out the usual dirt, debris, leaves and...

www.gmsquarebody.com

Here's what I did over the course of 3 days with no rain. Easier to do than I initially thought.

So there wasn't much prep except to clean it out? I cant get my hands down inside there to sand or pry out the old seam sealer.

Didnt know Permatex made an undercoating. I have some 3M but it would be a mess to work with there. It sealed ok?

 

[legopnuematic]

If you pull the kick panels off, along with the cowl screen, that gives access into the vent buckets.

I’d recommend getting/using a 2 component seam sealer.

This from Eastwood is decent stuff, just be careful where you are spraying (easy to shoot it everywhere if not careful):

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SEM sells a cavity wax that has a spray tube as well. Might be good after sealing.

 

[legopnuematic]

On my friends 75 K5 I did end up cutting the cowl off, due to the rust in the seam, and welded it back on.

Not actually that horrible of a job to do.

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[pinballlarry1]

When I cleaned mine out with a vacuum, there was only light surface rust left. I had no actual rusted out areas or open seams. I did remove some small areas of cracked sealant, but I was pleased that it looked pretty good after all the cleaning, degreasing, and spraying in the Permatex rubber goo. Even the chemical smell dissipated after a few days. Haven't seen water on the floor of the cab since.

 

[legopnuematic]

Couple more pictures from the Blazer.

Got worse before it got better

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Donor metal being welded in

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"New" vent buckets and original cowl/booster reinforcement all reinstalled.

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[Grit dog]

Seen alot of how-to's here with the idea of cleaning and sealing the inside leak-prone areas of the cowl. A pig in a poke with whatever sealer you use. So I'm about at that point and was wondering.....when someone says "open up the cowl" - exactly what are they referring to? Cutting the grill off and re-welding it? (not happening) My cowl is 100% cleared and raw steel - needs sealed up. I can stick the paint gun down in between the grids but thats going to make a mess. Cant see a seam sealer caulk tube fitting very well either.

Just wondered what the secret is to getting in there and seam sealing/painting/whatever the whole thing?

Thanks fellas.

Don’t worry about it. Your truck will never rust out there. Because it’ll probably never see rain. Lol
But to answer your question, yes the coating stuff @legopnuematic posted will take care of the “paint” part of it. But it will come out of every hole and seam. Make sure everything is covered you don’t want splattered green.

I tried rattle can undercoating thinking I could pile it on thick enough to basically “caulk” the seam. Didn’t work. Not high solids enough. When it cured it shrunk and cracked down the seam line.
I just used seam sealer over that. And should have just used it in the first place. Get what you can out of the tube nozzle. Do the rest by braile. Put a glob on your finger, reach in and fill that crack! (Sorry, no other way to describe the last part with out it sounding dirty…lol)

 

[Steelbuddha]

This is helpful. I've been trying to figure out where the water on the cab floor came from -- especially with new weatherstripping. It never ends.

 

[peats]

I used a double fiberglass mat to bridge the seam seal joint then added 3 coats of bed liner to the entire cowl area.