Before I do the plunge, and change the Heater core, is there something I am missing?

Its a 1999 Expedition 4.6l.

Here is the problem, The heat only lasts about 3 seconds before it starts blowing cool air. I already changed the thermostat thinking it was stuck, but no luck. I tried to find a vacuum leak or a hose being removed, but I couldn't find one either.

Also had the coolant flushed as well.. nothing seemed to work.. any ideas?

 

Have you checked the heater hose temps?

Checked for a broken blend door?

Steve

 

Also check to see if the hoses are good and hoot. It typically would not be your heater core if it is not leaking in your floor board, or having that strong smelll of antifreeze.
Check your flap door that changes the heat from cold and make sure you can hear it moving. Also i cant remember if it is electric or manual on the switch for the cold/hot on the temp setting, but if the switch is bad or broke that would cause it as well.

 

The heater hoses get hot, there is a T, on both hoses, For the rear core... and the hoses are hot...

I took the trim panel off around the radio, and looked down in there, and I can see that one moving around... where is the blend door located??

Can I see it without tearing apart the entire dash?

It just seems so wierd, like once you start blowing air after about 2 seconds its cool again..

I checked the ****, its not broke either.. hmm.

 

I can hear the actuator, I am gonna guess its inside the black housing... sounds like its lower on the passenger side close to the middle.

I can't hear any creaking like on the upper door.. that I could see moving when the Expy is running..

 

Your blend door is busted. The airflow is blowing it closed.

Steve

 

I dunno man,

I was looking at it agian tonight, after reading all the blend door quick fixed and stuff on the net, unforunately I can't do this becuase my plenum is the new style, and I can't get to the bottom of it. I can see the actuator, which is on the bottom of the plenum just inside, towards the middle.

I can see it turning, and actually can see the part that it hooks to turning too.. so I am not 100 percent sure the blend door is busted...

But in my efforts to reach up to turn the heat blend **** on the panel, I had my head really close to the bottom of the plenum and i heard water slushing around inside.. when the door came full closed and went back open, so I am back to thinking its the Core itself leaking or something.

I just wish there was some easier way than to have to take the entire freakin dash out.

WTF was ford thinking

 

well

I tore apart the entire freaking dash, got to the plenum, took the cover off, and what do I find.. a perfectly operating blend door, and no fluid. so what was I hearing?

maybe the foam I dunno... anyways here are some pictures.. I plugged everything back in, and the truck is idling in the garage now, waiting for it to get warm enought... the temp is almost up.. and the core is hot. I can barely freakin touch it..

SO why wasn;t I getting heat??










I dunno the AC Condenser is FREEZING cold too... could it be just my control panel itself not shutting the AC off? so the Cold air is overtaking the warm no matter what the blend door is doing???

Man I am gonna be sooooo pissed if its the damn panel.

 

Going to bring this one back from the dead....

I am still having heat issues... Still no heat.. anyone have any ideas what so ever?