How do I fix a leaky cowl?

Cowls leak for one of two reasons: either the sheet metal has rusted through, or years of debris (dirt, leaves, small animals) has accumulated around the cowl "hats" (extensions of the vent tubes into the cowl) allowing water to overflow the vents.

If the cowl is rusted, the only way to fix it permanently is to remove the rusted areas and weld in new sheet metal.

Unfortunately, the cowl is welded shut in early Mustangs (1965-68). To repair it properly, you will have to remove the front fenders, the hood, and the windshield, then separate some 130 spot welds. Then you need to cut out the rust and weld in the new metal.

There are a couple of less intrusive methods that you can try:

• Plastic hats---You can buy a repair kit that consists of plastic inserts (called "hats" because of their shape) that are shoved up through the air vents under the dash and glued into place over the vents using a silicon adhesive. You will first have to reach up through the vent and remove the rusted portion of the original vents that sticks up into the cowl. You should also scrape the cowl as clean as possible and treat the metal with a rust inhibitor, like Rustoleum or POR 15.
• Enter the cowl through the side---You can get into the cowl without breaking the spot welds by cutting two vertical slots up the side of the cowl (remove the front fender---the cowl side is the "inner skin" that is beneath the fender) and folding the sheet metal up; reach inside to clean the cowl interior, treat the rust, and install the plastic hats. Fold the metal down and weld it shut, then reinstall the fenders.

See the Vintage Mustang Forum topics Cowl repair and etc. update and Cowl Repair Kit.

See also the website www.geocities.com/tncub67Mustang for a graphic display of one Mustang owner's cowl repair project.