99 F150 no heat after heater core replacement

allthem · #1 07-30-2009, 03:12 PM

I have just finished replacing my heater core the job went well. i started it to let it warm up and noticed i was getting no heat and that my reservoir was backing up with fluid. i have since drained the system again, pulled the heater core in and out hoses from the engine. i can blow air through them, and the core, so its not clogged. i am guessing that it could be that i need a new thermostat?

Any thoughts and ideas appreciated.
thanks

Register today or sign-in to remove these ads!

allthem · #2 07-30-2009, 03:56 PM

i think i found the problem.

looking a little ruff

allthem · #3 07-30-2009, 05:29 PM

that was it. everything working out just fine now.

fordmaster · #4 07-30-2009, 05:32 PM

Any time you do a core, hose, water pump or flush install new thermo. Prevents this exact thing. I have had situations where I went through 2 new thermos before one was good.

tjstrike · #5 07-31-2009, 04:17 AM

This is the link I used, hope it will help.

I replaced my blend door and heater core. Happy ending!

allthem · #6 08-02-2009, 03:25 PM

i used the same install instructions. they were a great help and written very well.
lesson learned on just going ahead and changing the thermo. thought i could shortcut it and save a few bucks. i was wrong and ended up spending a few more.
oh well. it works and smells great now, and my wife thinks she needs to bring a coat with her now

thunder691 · #7 10-09-2009, 06:15 PM

i found it to the only way out for the water is thru the air blending motor hole the motor on my truck was full of water i took it apart and cleaned it up works fine now.

longbowdude · #8 10-12-2009, 01:46 PM

I just changed my core on a 99 f150. Everything has been working fine for a couple days. Should I bother with the thermostat?

wutagoalie · #9 10-12-2009, 05:21 PM

if it works fine, leave it!

Triton_98 · #10 10-15-2009, 06:01 PM

I wish i could say the same. mine blows frigid air even if it is set on hot..new core, new t stat, i can hear the blend door actuator when i turn the knob.. so idk

freezinjp · #11 11-08-2009, 03:35 PM

I replaced my heater core and thermostat myself but I still have no heat could it be the door not opening in front of heater core?