Disintegrating foam on a/c blend doors

[RDMueller]

Doing some much needed repairs to the HVAC on my 2001. Pulled the plenum from the truck and will be replacing both the evap and the leaking heater core. It was definitely a mess in there with 20 years of accumulated junk! Anyway, the foam on some of the blend/control doors is completely disintegrating and falling off. Even so much as touching the foam just causes it to crumble and fall off.

Just curious what the main function of the foam is, sound damping? Temperature insulation? There is nothing actually wrong with the doors themselves, just the foam. I’m thinking about removing the foam and possibly installing some weather stripping to ensure a good seal. Other than that, I can’t really come up with a good way to replace the foam unless I just get all new doors. Appreciate any words of wisdom!

 

[JDiehl]

So that's the foam I find on the dash after running the defrost!

 

[RDMueller]

So that's the foam I find on the dash after running the defrost!

Yep!

 

[bcbender]

Had a TDI Volkswagen that spit that foam out for years, finally stopped, and things function just the same, I assume its more for sealing and NVH, but not an expert here.

 

[Bamtech1]

I put some Frost King duct insulation on my doors when I redid all that stuff. It’s foil faced, seems to work. I think it’s some part insulating and some just to stop clattering. In fact I did the whole cab floor, firewall and back wall with the same stuff. Comes in a 16” wide roll at the home despot

 

[Brian Neal]

I've gone through two HVAC boxes, and only replaced the foam gasket on perimeter so it would seal off when closed. Neither made any noise that I could hear for the last 5 years with that ol' Cummins clattering away

 

[JeepBuilder]

I restored a heater in a full size jeep by using foam and rubber sheets from Grainger and or McMaster Carr. The glue is 3m and is on one side only. Cut to size, peel and stick. You can select thickness, size and material. Like new when you are done.