This is the heater box gasket kit I used to reseal the heater box on my 1966 Mustang. After 50-plus years, my original gaskets had crumbled into a fibrous mess that was stuck to the metal, and air was leaking past the seams.
A fresh set of gaskets seals the case halves, doors and openings so the air goes where it should. The kit fits the 1965 and 1966 Mustang heater box.
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Heater Box Gasket Kit at a Glance
- Fits 1965-1966 Mustang heater boxes
- Replaces the original gaskets on the case, doors and openings
- Includes an assembly diagram
- Adhesive is not included
Why I Used This Gasket Kit
Resealing the box is the heart of a heater box rebuild. Once I had the box apart, cleaned and painted, there was no point putting it back together with crumbling original seals.
One heads-up: the instructions in my kit were hand-drawn and hard to follow, and they didn’t say what adhesive to use. Plan on laying everything out before you start.
Who This Kit Is For
- Anyone rebuilding a 1965 or 1966 Mustang heater box
- Owners chasing weak airflow or air leaking around the heater box
- Anyone replacing the heater core or blower motor while the box is apart
How I Installed It
- Tear down the heater box and scrape every bit of old gasket material off the metal.
- Clean the surfaces with acetone or lacquer thinner (not WD-40) and paint if needed.
- Lay out each gasket next to the part it belongs on, using the diagram.
- Glue the gaskets in place. Black RTV worked but dried slowly, so I switched to Gorilla Glue spray adhesive, rated for foam and metal.
- Reassemble the box and clip the case halves together.
See It in Action
I used this kit in my 1965-1966 Mustang Heater Box Rebuild. The post and video walk through the whole job, from pulling the box out to reinstalling it.