Cowl Drain Info Wanted/Weldless cowl repair?

[andy72]

Can someone give me detail about how the cowl drains on my 72 mach?

I assume out each side into the inner fender area.

How big is this hole?

How do you clean it out?

Is it tubed or just an opening in the sheet metal?

Should I be able to feel it when I reach my arm down the cowl and reach over the "hat " that the heater box mates to?

My cowl has a few pinholes in it from rust. I would like to patch a few and then maybe seal the others.

Future proper drainage is what i'm getting at.

I really don't want a cowl replacement project.

Anybody sealed theirs up in another way?

I was thinking POR15 both sides, POR 15 epoxy putty over the 4 or 5 small pin holes, Eastwood seal sealer over all this.

Any thoughts?

 

[mach1000]

Just a few comments: I "repaired" my cowl vent hats in my 71 with aluminum flashing. Easy to work with, cheap and wont rust. I hand made hats and used Eastwood seam sealer to seal them in place. I also used the seam sealer as a "liner" around that area from the underside. I thought I posted pics of the job cant find them. I simply took as strip of about 4" wide aluminum flashing, made a 1/2" or so right angle bend on it and overlapped the ends and riveted it together to make the hat. The diameter should measure tight the area in your cowl vent. You can measure it once you remove the fresh air plenum. (drivers side, pass side you need to remove heater box) Seam sealed the crap out of the cowl vent area, pushed the homemade hat up there, more sealer and installed fresh air plenum to hold it in place. Temporary/permanent fix but worked. I also pulled the cowl grilles out and sealed all that area as much as I could reach with seam sealer and undercoating. I supposed that rhino lining stuff would probably work good or even that gutter/roof sealer spray they sell at the big box hardware stores. It's supposed to seal roofs so why not cowl vents! One of those inspection cameras they sell cheap at harbor freight would probably work good to do an invasive inspection to see how rotted that area is but you can reach in from the vents or once you remove your plenum and feel if the hat is rotted out. Pin holes not so much which it why I'd seal it all with undercoating or something like that mentioned above.

 

[Stanglover]

Here is a picture of the cowl drain on my car. It is basically an open hole, but these get blocked all to easily. I sealed my cowl inside with a liberal coat of stone chip undercoating, then sprayed it black. Hope this helps.

 

[Carolina_Mountain_Mustangs]

The issue with the cowl rusting was not drain issues just raw unprotected steel that rusted fast. When they put the lower cowl they smeared some sealer around and did not do a good job then the upper was welded on. Rain water, water when you was the car salt from the road get in there and they rusted really fast on some cars that had bad sealing jobs.

What you are proposing would be a temporary fix to a major issue. Along the bottom of the windshield you will find a gap between the cowl and the windshield that you can stick you fingers in. That get trash in it holds moisture and rusts out the upper cowl. Run a wire in and see if you have holes there.

No easy way to do a permanent fix on a cowl. Cowl leaks are usually what takes the front floors out with rust.

NEVER wash you car with a hose or pressure washer it feeds the rust in lots of different places. Bucket of clean water and micro fiber towels and rinse a lot. That is unless you go to mud races and really need to wash it, lol.

You should also add mess wire under the plastic grills, paint flat black, to keep the mice out and I also put a second piece between the heater box and the cowl to make sure they never get into the heater box again.

 

[mach1000]

Great idea!

Can't tell you how many pounds of mice nests (and other matter) I've shop vac'ed out of heater boxes over the years!

The issue with the cowl rusting was not drain issues just raw unprotected steel that rusted fast. When they put the lower cowl they smeared some sealer around and did not do a good job then the upper was welded on. Rain water, water when you was the car salt from the road get in there and they rusted really fast on some cars that had bad sealing jobs.

What you are proposing would be a temporary fix to a major issue. Along the bottom of the windshield you will find a gap between the cowl and the windshield that you can stick you fingers in. That get trash in it holds moisture and rusts out the upper cowl. Run a wire in and see if you have holes there.

No easy way to do a permanent fix on a cowl. Cowl leaks are usually what takes the front floors out with rust.

NEVER wash you car with a hose or pressure washer it feeds the rust in lots of different places. Bucket of clean water and micro fiber towels and rinse a lot. That is unless you go to mud races and really need to wash it, lol.

You should also add mess wire under the plastic grills, paint flat black, to keep the mice out and I also put a second piece between the heater box and the cowl to make sure they never get into the heater box again.

 

[Mister 4x4]

My cowl was packed full of leaves and pecan shells - the plastic factory 'screens' were firmly in place.

+1 on the idea of adding some fine mesh on the backside of the factory screens, to help keep as much debris out as possible.

 

[Stanglover]

My cowl was packed full of leaves and pecan shells - the plastic factory 'screens' were firmly in place.

+1 on the idea of adding some fine mesh on the backside of the factory screens, to help keep as much debris out as possible.

Yes definitely a good idea on the screens at back of the factory ones. I get those pesky little Locust Tree leave in my cowl should I leave the car out in the driveway. Another little "project" for spring!!

 

[Qcode351mach]

I did a write up how to about 4 years ago on keeping debris out of the cowl

Here it is again

http://www.7173mustangs.com/thread-how-to-keep-your-cowl-debris-free

 

[Carolina_Mountain_Mustangs]

We all think alike, lol. You know Ford use to put the screens in back in the 50's all of my 1950 fords have them out front and there are filters for the air coming into the cabin that just made a comeback a few years ago. Now most cars have cabin air filters. I have some NOS for the 1949-51 model. Mice never have got into my old cars because of the wire and filters is why I did it.

 

[andy72]

Here is a picture of the cowl drain on my car. It is basically an open hole, but these get blocked all to easily. I sealed my cowl inside with a liberal coat of stone chip undercoating, then sprayed it black. Hope this helps.

Thanks! Awesome pic. didn't feel anything that large when sticking my hand down the cowl.