Please help cool heat!

[Fordracer666]

So I just bought this nice 99 ford expedition with a 4.6l
My problem is I have warmish heat when I keep my fan on low.
But as soon as I crank it up it. Cools down. I've been doing alot of searching
And can't find a definitive answer. It acts the same front and rear.
And the hoses don't seem to get so hot I can't hold them!
So here's what I have done already

Changed Tstat
Changed water pump
Flushed water through the heater core seemed fine

It seem like both heater core hoses get hot
Not super hot though! And the upper radiator hose stays fairly limp
Like its not building pressure. So I have searched all over
And I see similar problems . But i don't know what to look at next.
It seemed like it warmed up sitting at a idle . And my temp
Seems perfect.


What to do next? Any help is greatly appreciated.

 

[Fordracer666]

Heat

Should I cut the hole behind my glove box
And check the operation of the blend door and
Also feel if the core is hot? Should that be my
Next move? Really sucked with no hear this morning!

 

[Fordracer666]

Heat

Wow no help anyone???

Well here's where I'm at now.

I cut a hole in the heater box from the glove box
The heater core get nice and hot
Both sides. And the blend door works flawlessly .
So here's what I noticed while looking over everything.
The upper hose was limp until the truck
Fully warmed up and then it had a little pressure in it
. And it doesn't get burning hot like it should.
And I felt the lower hose and I was cool not warm at all??
The coolant is full and the trucks temp
Is perfect. So what gives ? Please I'm begging for help!

 

[Fordracer666]

Help

Someone please help!!

 

[dougmcp]

Patience grasshopper.
It sounds like it's airlocked.

BTW 666 is a pretty unlucky number, does it have some meaning?
Who knows that might even be your problem.

 

[pooleo8]

Yeah, the blend door and actutator would have nothing to do with it. As you said both front and rear has the same symptoms.

Check your bottom radiator hose, you might have a partial plug in the rad.

Also, is there a vacumm operated valve like on the rangers? This shuts off the flow of water to the heater core. Might be partially closed.

 

[Fordracer666]

Yeah, the blend door and actutator would have nothing to do with it. As you said both front and rear has the same symptoms.

Check your bottom radiator hose, you might have a partial plug in the rad.

Also, is there a vacumm operated valve like on the rangers? This shuts off the flow of water to the heater core. Might be partially closed.

No there is no valve on the heater core hoses.
Seeing that the lower hose is cold . Maybe I have a
Faulty new Tstat !

 

[Fordracer666]

Patience grasshopper.
It sounds like it's airlocked.

BTW 666 is a pretty unlucky number, does it have some meaning?
Who knows that might even be your problem.

666 is my lucky number lol
So how do I get the air out of the system?
I've drivin it a few hundred miles after all the work
I did.