just found out tonight that my heat will only blow out luke warm. when i got home i took a look at it, heater core appears hooked up, blower motor works, truck heats up fine and doesnt overheat so im sort of at a loss. is there something else im missing before i change the heater core? it used to have ac but was removed before i acquired the truck. thanks for any help!

 

Try doing a coolant flush first then burping the cooling system. You might have an air bubble in there.

If the heater core isn't leaking, then I'd leave that for a last resort option.

 

u might want to try just flushin the heater core by takin the line off the water pump and intake manifold and pouring some flush down the line and then use some volume but not pressure and see what comes out and then rereverse flush it