NO heat!!! thermostat?

[NeXtras]

so its a blistering 7 degrees here right now and i have no flipping heat in the truck.. used to be pretty decent..

possible its the thermostat?

 

[polarbear]

Is the guage reading? Heater core could be plugged too.

 

[Mil1ion]

What does the temp gauge say ?

Try placing some cardboard forward of the rad as to not block the rad fins off from air. I like to put 5 holes in mine
1 in all 4 corners and 1 in the center.

If it still won't get warm and toasty..verify the T-stat temp

Use no less than 180*F

Make sure you verify the coolant temp with a candy thermometer and the rad cap off when at normal operating temperature.

 

[Skandocious]

Yup check gauge reading. If it shows normal operating temp then you've got a clogged core/hose.

 

[TexasNomad]

I don't know about his year truck, but isn't there a small vacuumed power valve in the hot coolant line going to the heater core?

 

[polarbear]

If it has factory A/C, I believe you're correct.

 

[TexasNomad]

Thanks Bear
Yeah you might want to check that valve and see if its working, had one go bad on my truck I nearly tore the whole truck apart trying to find why my heater stopped working.

 

[Skandocious]

I don't know about his year truck, but isn't there a small vacuumed power valve in the hot coolant line going to the heater core?

On the heater hose? I have factory ac and I've never noticed that valve... And I just changed my coolant last weekend.

 

[TexasNomad]

Never mind I went and looked and it doesn't have that valve..

 

[subford]

On the heater hose? I have factory ac and I've never noticed that valve... And I just changed my coolant last weekend.

The vans (88 E150) have them and some large cars (71 Fords).
They give you a little extra cooling in the large passenger compartments.

NeXtras:
Make sure the Blend door is going all the way and nothing is the way of it like a pencil or pen that dropped down from the defrost vents.
The Blend door is cable controlled and not vacuum.

 

[Skandocious]

The vans (88 E150) have them and some large cars (71 Fords).
They give you a little extra cooling in the large passenger compartments.

NeXtras:
Make sure the Blend door is going all the way and nothing is the way of it like a pencil or pen that dropped down from the defrost vents.
The Blend door is cable controlled and not vacuum.

Which blend door is that Bill? I thought all the blend doors were vac controlled in my truck...

 

[TexasNomad]

I believe there is only one, if you look under the dash on the passenger side Chris your going to have to get on the floor to see it, but there is a small door that is vacc controlled, the other one you can't see the way to know if its working is to opening your hood and right behind your blowing box you will see the vacc valve for it.

 

[Skandocious]

I've got a blend door under the dash (the one you mentioned) that is vac controlled, and I've also got one on top of my blower box which is also vac controlled. Is that the one you're talking about?

 

[TexasNomad]

Yeah thats them

 

[subford]

All blend doors are hand cable operated from the 1950's to 1996.
1997 and newer trucks maybe also but I do not know about them.
Yes Skandocious yours is hand cable operated too.

1992-1996 vent system:
http://i54.photobucket.com/albums/g91/subford/AC System/Hold/ACVacuum3.gif

Before 1992:
http://i54.photobucket.com/albums/g91/subford/AC System/Hold/054-01.jpg

/

 

[Skandocious]

Bill I'm absolutely positive that both of those blower motors have vac lines running to them. I know the one on the blower motor has a vac line because I had to repair it. And I know the blend door under the dash is vac operated because my damned air switches from vent-to-floor when I load up the engine

 

[subford]

Bill I'm absolutely positive that both of those blower motors have vac lines running to them. I know the one on the blower motor has a vac line because I had to repair it.

That is not a blend door, the one with the white vacuum line under the hood is the outside/inside air door.

And I know the blend door under the dash is vac operated because my damned air switches from vent-to-floor when I load up the engine

The vent-to-floor is not a blend door, it is the Floor/Defrost Door.

The blend door only controls the air temp and not where it goes or comes from.
It blends the cold with the warm air to the temp that you want. That is why it is called a blend door.

Did you look at the diagrams I posted above?

If the vacuum doors change when you floor it you have a vacuum leak somewhere most of the time.

This knob on your dash goes to the cable control blend door:

 

[Skandocious]

Ahhhh okay-- I was looking at the wrong part of that diagram. My bad Bill-- looks like you're correct.

 

[NeXtras]

my temp gauge gas never worked the right way.. sporatic if anything.. dunno how to check blend door

 

[Skandocious]

If your temp gauge is jumping around then you've most likely got air bubbles in your coolant.