Cowl

[n_reckless]

Like many others I also have a rusted cowl with passenger side leak. I'm not really concerned about it because I'm going to paint the car in the near future and will also do all the bodywork I have to. I'm just looking for a temporary solution until I'm ready to bring my car to the bodyshop. 

I already sealed the vents (I don't need A/C) , put rubber under the vent screens, sealed the whole thing with silicone also around when I put them back on the cowl. I had a little leak on the driver side but since I sealed it nothing. The strange thing is that I still have water leak on the passenger side. I double checked the vents and everything is sealed from the outside so water not supposed to enter anywhere.

Is there other locations other than the vent screens where water can enter inside the cowl what I probably overlooked?

 

[vintageman]

Could it be your heater core leaking, when I have anything wet on my passenger side, that is one of the first things I think of. Good luck with the cowl repair.

Tom

 

[tony-muscle]

You could have rusted through sheetmetal somewhere. Suspect places could be at the hat juncture or between the hat and inner fender.

Sent from my SAMSUNG-SM-G930A using Tapatalk

 

[Bentworker]

Heater core is a possibility

So is condensation from AC

Also, rot under the windshield creating a hole into the cowl is always a possibility (pretty common).

Last thing is that the cowl has an opening on both the driver side and the passenger side that ports inside the fenders.

 

[tony-muscle]

In this thread I show how I fixed the rust of my cowl. Look at the pictures there and you can see some areas where the sheetmetal was rusted through.

https://www.7173mustangs.com/thread-my-method-for-cowl-repair

 

[kcmash]

When Does it get wet?

1) After Rain or car wash?

2) After driving ?

3) all the time

4) After long AC runs?

If After driving, you may bypass the heater core and see if it stops.

You might also crawl under the passengers side firewall and stick a wire up the drain hose to make sure it is clear.

Sometimes(especially with cowl rot, the heater box drain will get clogged and water will accumulate in the heater box.  It can spill out when rounding corners, etc.

Good Luck

kcmash

 

[n_reckless]

I don't think that the heater core. It only leaks when it's raining but the water definitely coming from the cowl (through the bottom of the heater box what is already rusted out).

Under the windshield is fine. I checked the repair guides on the form but unfortunately I'm not that skilled working with metal. 

That's why I try to do temporary fixes until I'm ready for the paint/body work.

The frustrating part is that I already filled some holes inside the cowl and already sealed the cowl vents completely and it's still leaking.

Assuming that the whole cowl sealed from the outside perfectly it wouldn't matter how bad is the bottom when there's no way that water can get in. But still find a way to enter somewhere.

 

[n_reckless]

I made pics what I did before. Like I said I don't care about how it looks like because the car will be stripped for the bodywork. I just want to keep the floor pan in good shape to avoid any additional work.

The first is the sealed cowl and the second is the pass. side fender where I smeared a little polyurethane. Still thinking about where the water can enter...

 

[Carolina_Mountain_Mustangs]

All it takes is one tiny little pin hole to let the water in. I am betting under the edge of the windshield. I have seen lots of rust in there when you cut the windshield out.

Might also be the roof rain and running down the A post and in the car. There are several large rectangle holes that locate the drip rail molding. Ford used a sorry foam tape to seal that area and it never does. My brand new 73 leaked the day I got it filled the floor with 2" of water.

I use the strip caulk by 3-M instead of the tape.

 

[n_reckless]

All it takes is one tiny little pin hole to let the water in. I am betting under the edge of the windshield. I have seen lots of rust in there when you cut the windshield out.

Might also be the roof rain and running down the A post and in the car. There are several large rectangle holes that locate the drip rail molding. Ford used a sorry foam tape to seal that area and it never does. My brand new 73 leaked the day I got it filled the floor with 2" of water.

I use the strip caulk by 3-M instead of the tape.

Thanks, I'll check the edge if the windshield. I just did the weatherstripping not so long ago. Also took apart the drip rail. I also put silicone around the drip rail where it meets the body just to seal everything temporary. As far as I see the edge if the windshield where's a gap between the dashboard at the edge of the pillar is dry in rain.

 

[Don C]

Around the wiper pivot is another possibility, as well as the screw that holds it to the underside of the cowl.

 

[donkost]

These cars leaked when new, so it's almost guaranteed 46+ years later. Also, is this a daily driver where it sits out in the rain? Probably not the optimum environment for a car you are looking to restore. But if that's what you have to do then so be it. I did the same thing when these types of cars were only ten years old because I was using it as a daily driver for school, work, etc.

 

[Carolina_Mountain_Mustangs]

I would suggest you stay away from using Silicone caulk on any part of a car. It is made for your bath not a flexible body of a car.

Also the silicone in the caulk can play havoc with getting fish eyes in your paint. Having worked as a stamping supplier to several mfgs.. We had very specific rules of what lubricants and sealers that could be allowed into the plant. We had an employee that had to approve the purchase of any of those materials. You can shut down and entire car plant by having a very small amount of silicone on the parts you supply. We could not use Silicone caulk in the stamping plant and no lubricants with silicone.

It cost John Deere millions simply because one of the Silicone rubber wrist bands supporting breast cancer awareness fell into one of there wash tanks on the paint line. They had to dump all the tanks and wash and wash.

Even under arm antiperspirant that has silicone in it will cause fish eyes in your paint.

At the local Tech College some idiot brought a bottle of Armor All into the body shop class to detail their car. It screwed up the down draft paint booth and required that the filters all be tossed and they had to steam clean over and over. Any product with Silicone should never be in your garage or on your car.

Use automotive body seam sealer or 3-M strip caulk. There are specific types for different areas of the car.

When you see a new car that the paint peels on it is probably because some idiot contaminated the parts coming to the assembly plant. Can cost millions for just a small mistake.

Here is a link to information so you know I am not just blowing smoke. https://www.kcprofessional.co.uk/media/63046178/KCP_Silicone_Contamination_Guide_from_Kimberly-Clark_Professional.pdf

Another tip for everyone is do not use rags or cloth shop towels that have been washed. Dryer sheets usually contain silicone. Use only paper shop towels that are known to be free of silicone.

If you do your own paint work do not use an antiperspirant it will have silicone in it. You can use a deodorant but check the label to see what is in it. Also wear a disposable painters coveralls and tape up the wrists. Will keep any contamination from your clothing off the paint job.

If you have ever fought the battle of fish eyes in your paint you will know how difficult it is to get rid of them once there.

Ok I am off the stump for now.

 

[n_reckless]

These cars leaked when new, so it's almost guaranteed 46+ years later.  Also, is this a daily driver where it sits out in the rain?  Probably not the optimum environment for a car you are looking to restore.  But if that's what you have to do then so be it.  I did the same thing when these types of cars were only ten years old because I was using it as a daily driver for school, work, etc.

Yes my daily driver, fortunately no rust other than the cowl. Everything else is pretty solid. I calculated with replacing the whole cowl when I'm ready for the paint and body work financially. My case is a little bit difficult because I don't have another car so have to plan everything way ahead especially for a longer project like paint what can take months.