heater problem

I have an 1995 F250 4x4 5.8Lit no A/C the heat blows cold to warm when I throw the heat switch it moves the linkage the heater core is to hot to tuch so i know that is working and both hoses to core are hot my blow is working fine (after replaceing both resistor and wire harnes )any sujestions I'm lost
Thanks in Advance

Either the blend door is leaking/not closing fully against the cold air inlet, or the core is plugged not allowing enough air thru it.

Either the blend door is leaking/not closing fully against the cold air inlet, or the core is plugged not allowing enough air thru it.


i'm getting good volum of air how do i clear it if its plugged would it be accsessable from the fan if i remove it or do i have to remove the core its self