The Stovebolt Site Forums The Shop Area Paint and Body Shop Cowl vent leak on my 52 Chevy 3100

I have a leak coming from the cowl vent on my 52 Chevy 3100. I've done a search on the Forums and based on what I've read, here's what I've concluded:

I'm not spraying the water too forcefully. I used a hose to gently run water down the windshield and over the vent.

I don't think it's coming from the rubber seal. I installed a new rubber seal (from Steele Products) after cleaning all the old seal, glue and rust from the vent. I used a good weather stripping adhesive (3M). I also installed a new vent drain hose.

When I look under the dash, the water seems to be coming from around the outside edge of the vent assembly, not from the inner part where the gasket seals the vent.
Cowl Vent Leak Photo

If this is true, what is the best way to seal that joint? I assume it was originally spot-welded to the underside of the cowl and has finally separated enough to leak. I'm thinking of cleaning away the surface rust and using a silicon caulk. Is there something else that would work better?

If it's that rusty on the cab side how rusty is it on the other side where the moisture is actually traveling? I'd try removing/cleaning up all the rust around the vent panel so I know how pitted it is and then I'd be pulling the vent door and looking with a mirror at the hidden side and seeing what that looks like. It looks to me like moisture is sitting on the lip that's formed on the back side of your arrow and that would be where I'd try to clean/seal things up. I'd stay away from silicone as it creates problems if you ever want to paint.

I had already cleaned up all the rust I could reach from the top when I had the vent door off to replace the seal. I put on two coats of the stuff that turns rust black. The channel is only about 1/4 wide on the top, so I wouldn't be able to get a mirror in there. The only way I could see to seal it from the top would be to completely fill in that 1/4 channel. Didn't know if that would cause more harm than good.

If you only have 1/4" I guess you could try some self healing seam sealer... I think I ordered mine from Eastwood. It has a applicator hose you can reach inside there with.

I looked at Eastwood, and couldn't find a seam sealer that came with an applicator hose. They do have a brush -on seam sealer that I might try.

This is the stuff sorry I didn't remember the name but it works good in those spots.

I found it, and it's on order.
Thanks.