74 charger heater core caulk?

[Hijinx]

My old heater core has caulk around it, not sure if this was some fix by a previous owner or if it came that way from the factory for a reason.

My new heater core has no caulk, if it's factory, anyone know what kind of caulk would be good?

 

[Billccm]

If you get a heater box rebuild kit from DMT it will have the seals.
Otherwise use foam weather strip.

 

[Hijinx]

yes i have the DMT kit, just wondering about the caulk around the heater core itself. The new one has no caulk around it.

 

[retractable]

I have seen caulk around many original heater cores. I think it was to seal any air leaks so all the cold air went thru the core to get heated up. I have used a good silicone to seal mine. The last core I replaced had some large areas that needed sealing.

 

[72RoadrunnerGTX]

I've used Permatex ultra grey gasket maker in that application. The chalking seals gaps between the heater core to it’s mounting flange.