How about using Flex Seal?

[tjvending]

What do you think about using a product call Flex Seal (TV add) for stopping small water leaks under the dash. I can see where water is coming from under dash but not on top of the cowl. By sealing it under the dash, do you think this will stop the leak? Leak is around the top under the dash by the gas pedal location. Thoughts on Flex Seal?

[GMtrucknut!!]

I would think it would seal in the moisture which would lead to future rust and rot.

[Agent915]

You will just be, as already mentioned, trapping the water creating an even larger problem down the road. If you can see where the water is getting in and you can get to it, fix it. I am in the assembly stage on mine and just recently got the cab back on the frame. I THOUGHT I had all the problems with holes fixed, that is til one day I had been doing a little wet sanding on it and opened the door and found a small puddle of water. Got a light and started searching under the dash. Sure enough.....another hole! It seems as though these trucks were shipped with rust. It wasn't an option. Most of the serious problems I had around the cowl and dash areas were from where the previous owners used silicone, or some other DIY solution instead of just taking the time to do it right the first time. Fix it the proper way and you won't regret it and the next owner will appreciate it too!! Trust me on this.

[brad_man_72]

I used it on the convertable top on my $800 miata as a joke, it worked.
I would never use it on my truck. Find the leak and fix it from the outside.
Posted via Mobile Device

[PAWS 72]

Been wondering how many would admit to using it. Also if it was any good.

[bigguy69]

I thought about spraying it on an under bed gas tank. It has been letting water in the tank.
Posted via Mobile Device