The Stovebolt Site Forums The Shop Area Paint and Body Shop 1950 Chevy 3100 cowl vent leaking

I have been trying for years to get my cowl vent to stop leaking, I have changed the seal, filled in holes, adjusted the seal several times. Does anyone know a trick get the vent to stop leaking, it's a real pain when it rains.

I got a cowl seal from one of the vendors that was supposed to be the greatest thing since sliced bread. It was way too thick and stiff and made the vent stick up above the cowl. I went with the more original style foam seal, although I haven't had my truck out in the rain yet to be sure it doesn't leak.

You might need to look at the lower edge of the vent that contacts the seal to be sure that it's smooth. Also be sure that the drain tube isn't plugged.

A good cork seal works best for me. A spring that's lost tension won't pull the vent down into the cork to seal out rain......the rubber gaskets have never worked for me on my 52 or the 37

Mike - One other thing to check is the drain tube itself. If it's not plugged, it could be it has a crack in it (they tend to get brittle and crack over the years). I would also check the rubber tube to steel drain tube connection. Did you apply any sealant to the metal drain pipe when installing the rubber tube? They were originally installed with sealant to prevent leakage at the metal to rubber drain joint, which is inside the cab and leakage would run down your firewall to the floor.

I have the rubber seal, sounds like I might need to switch to a foam or cork seal. I fixed the drain pipe and added a new tube, it works I know because water runs out of it onto the ground. The seal just doesnt seem to stop water from coming in though. If I get a new seal, should I use sealant like RTV? I had RTV on the rubber gasket and it still leaked.

I would put some sealant on the bottom of the seal.

Another thing to check is to be sure that there aren't any rust holes in the bottom of the trough where the seal goes. Those would need to be sealed up. RTV would work for that as well as for the bottom of the seal.

I ad a bunch of rust holes in the trough and patched them up with JB Weld, but the thing is still leaking. I think that I am not getting the rubber gasket positioned right, I also think I am going to switch to a cork or foam gasket. Thanks everyone!

Mike - Something to try with whatever gasket you use next. Once everything is in place, adhesive/sealant dried, etc., take a piece of chalk and rub over the seal surface that should contact the door underside sealing area. Then close the door (fully latched position) and reopen to check for chalk transfer to the underside of the door sealing surface. If you don't have chalk transfer all around the perimeter of the door sealing surface it still not sealed.

You should be able to see where it's not touching (no chalk transfer) and use that as food for thought on how to correct the problem (thicker gasket, more pull down on the operating latch setting, etc.). Best of luck and please let us know how things turn out.

I was chasing my tail looking for a "cowl vent leak", only to finally discover that the leak was coming through a screw hole in the cowl which holds the cowl hood seal in place. Those screws require sealant according to The Manual.

I use 2 foam seals. I put one where it belongs, and the second one on the underside of the vent door.
In order to make the one to fit on the underside of the vent door, you need to cut it to reduce the width and the length.
I tiny dab of weatherstrip cement will hold the cut ends together.

The foam is soft enough to fully close the vent.
The original seal relies on seal-to-metal contact to keep water out.
The use of two foam seals relies on seal-to-seal contact. It ain't gonna leak.