BMosely
Well-Known Member
In most cars it is the external corrosion not the internal corrosion that kills the heater cores. Leaves, bugs, nuts, chipmunks, and water. Let copper stew in that mess long enough and you get a new air freshener along with wet carpet. Just pulled down our 68’ Coronet original air box. Semi disaster as expected but prior to pull down the core and evaporator passed pressure tests. The design of the Mopar box drives the primary air flow in front of the evaporator first, flowing thru the heater core for discharge to the cab. Hence the reason for that little fire wall valve to bypass the core. Now I get it. The good news is all the trash, nuts, straw, etc loads up on the evaporator. I mentioned water. The evaporator has a drain pan so moisture discharges vs standing and stewing. The heater core stays dry and trash free. That is how it makes it 50 years.