Ive got a 2001 f150, and havent had heat since last year. Not totally cold but not enought heat to defrost windshield or keep you warm. Had a shop check it out, and there is flow through the heater core, both in and out hoses are hot. They replaced the water pump for the hell of it didnt help.

After that we turned to the blend door possibility, and you can hear it opening and closing fine. So we cut behind the glove box and made an access panel to the plenum box to make sure and see what we would find. The door is intact and working perfectly and the heater core is hot enough that you cant keep your hand on it while its running.

So that leaves me wondering? Not really sure what to do now? Just replace the heater core??

Thanks for the help!

 

I had that trouble with my 1998 F150......i changed the water pump and it got a little better....then i flushed out the heater core again.......it is much better.....cant say that it is 100% perfect but better........i think i am gonna have to run a cleaner or a flush thru it to get it exactly right.......there was a guy from 2006 that was called no heat dave and he replaced his water pump and fixed it..........i would not change the core if it is not leaking and it is not plugged beyond help.....i think maybe just a good flush or cleaning out.......good luck Don