Folks got a question and request for help. My 02 F150 V6 only blows cool air when set for heat. Did a bit of internet searching and factors involved. Radiator fluid is full. truck does not run hot (temp gauge shows normal), heater hoses=one gets hot the other feels cold when heater is "supposed" to be running. So I'm thinking it's either heater core is clogged or maybe heater control valve or blend door issue?? Any and all thoughts/advise would be appreciated.

 

Either the heater loop is clogged, the thermostat is bad, or the pump is weak.

 

Should have stated this as well. Had water pump replaced earlier this year so I doubt the water pump is part of the problem.

 

did you have heat after the pump was changed out maybe or hopefully a air block ? just a thought

 

If gauge is normal, then i would assume the thermostat is working also. I dont like the heater hoses, one hot, one cold idea. Im not sure there is a water valve on that truck. My 2001 5.4 has no valve. I think i would take both hoses off (heater) and connect garden hose to one end and flush thru good to see that if flows good... Also, turn the fan on very low speed, and the heater hose outlet should be about as hot as the inlet. Either no flow from heater pluggage, or some type of water valve.

 

I learned a long time ago (the hard way, of course) that just because something is new(er), it cannot be assumed to be good.