Cowl cleaning surprise!

After reading all the horror stories about all the rust issues that could possibly be in the cowl area I had to check mine. After removing the cover and screen there wasnt much debris there, after vacuuming and washing the area good I was pleasantly surprised "no rust at all"! The factory seam sealer is starting to crack especially on the drivers side around the wiper motor area. My question is should I use seam sealer or get some silicone caulk to put on this area, and also what is the best way to get it in there?

I lathered mine in no shrink flexible silicon and then flex seal over that. Correct way to do it? Probably not. Will it leak? Probably not.

I used the 2-part structural panel adhesive and let it run down each side. Pretty slick stuff, but a bit spendy.

I would not use caulk. I did that and it didn't quite last 8 to 10 years. Probably was not cleansed the best prior. But I would use seam sealer. It's for that purpose. I used AC delco on mine this last time.

I dont consider clear silicone as a viable option for that application. Ive heard some people in THIS msb speak of a product that is supposedly close to the original called SEM Seam Sealer

A review-

"It is OEM quality, and paint will adhere to it, but it does not mask off well. When you try to pull tape off around it, you'll have a mess on your hands. Takes a skin over set in 10 minuets, while still wet underneath.. The thinner application the better on painted exterior panels that show. Have fresh razor blades handy for trimming. How you lay it in is how it stays, so you'd better really like the visual. My learning curve was quick and steep. Best seam sealer I've ever used out of a tube, but keep it where it's supposed to be because it ain't moving once you set it!"

I chose to link their website here:
https://www.semproducts.com/products/repair/seam-sealers

Dude I even got a video with part numbers..

Thanks everyone for all the great ideas, probably going to go with the Sem, or the 3M fast n firm both sound like good products. Hopefully I can find some at the local part stores.

My cowl was really rusted badly and water would come into the cab. Since I am doing a cab restore, before I moved forward, my focus was on sealing up the leaks. The seam seal "seemed" to be intact. So, right or wrong, I used fiberglass resin and poured over the seam seal and then after cure I sprayed the cowl area with an undercoating product. I also sprayed the undercoating on the underside of the dash. Problem fixed. FYI, the seam inside the cab where the firewall and trans hump are soldered together was also leaking. I again used fiberglass resin and undercoating inside and out. I know it is not the perfect way, but I do not have the $s for a full tear down restoration and nor is there anyone in my area that will do it. More money in collision apparently.

For these types of repairs, try to find a store that sells supplies for body repair shops. The variety is much better than a standard parts store. For example, the standard store sells a couple types of rubbing compound, but the body shop parts store sells many grades of rubbing and polishing compound and the abrasive level is clearly marked on the bottles. I’ve never shopped for the filler you need, but I assume they also carry that type of material.

Bruce

I found some of the SEM seam sealer, it seems to be a very good product! I feel very confident the cowl area of the truck is sealed up and should be trouble free for several years. Thanks again for all the suggestions and product recommendations.

Wait wait wait wait.

You forgot to post pix of the fix ..

We're gonna need some FIXPIX pliz.

I dug all the factory seam sealer out. It was hard as a rock sanded out the rust , primed it all with epoxy primer (Dupont Corlar ) sanded it all again and then sealed with this solvent born polyurethane caulk.


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Good thing you posted this thread I didn't know about seam sealer. I was about to use caulk in there today. Now I'm gona find some of that sem seam sealer