ive had all the same problems and tried the fixes, but i did find out i have minimum flow of coolant to the heater core. im at at a loss. its a 2010 nitro
Seems epidemic judging by the number of questions on Didge Nitro heater cores in this site alone. This response seems most relevant to your question: https://www.cargurus.com/Cars/Discussion-t25045_ds617525 - mentions that the dealership told him the heater core can "plug up in stages" and can appear to be flushed out with good flow when in fact still has blockages.
yes but even the feed hose has hardly any flow going into the the heater core.
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