Air conditioning "insulation"

In checking a blob of gooey, black, asphalt looking material (the texture of a really soft, flexible roof shingle) that fell from the engine (1968 302 2bbl), my shop showed me what they say is some sort of spray on insulation for a part of the A/C that comes through the firewall on the passenger side. Aside from the fact that it’s a really slopping looking job, I’ve never seen anything like this and clearly it’s not holding together. Has anyone seen or used anything like this? Assuming it is some sort of insulation, should that A/C part even have insulation there? If so, what is a better product to use?

Thanks in advance.


Yes it is used to insulate the expansion valve for the AC in the engine compartment. I think you can get a new “glob” of it from the likes of vintage air.
The expansion valve is a metering device that effectively meters the Freon causing it to expand rapidly where it passes through the evaporator coil on your car and during that expansion it absorbs heat passing through to coil in your car. I would replace the insulation if you use your AC.

You might try this: . John

Thanks very much C7XR7 and 68PUMA. I took a second look at the car a few minutes ago and there was another piece that had fallen off so it wasn’t the greatest of jobs. The WCCC product looks similar but thinner so I think it would be a cleaner application compared to what looks like a clump of Play Doh on there now.

Another question if you don’t mind commenting - how thick should that insulation be?