No heat in the cab... brrrr

[osus86diesel]

Here is the deal. If the truck is driven for a half hour or so on the interstate there is still no heat to the cab. I have check the doors and mixer and they operate properly. i have also checked the heater hoses to and from the heater core and they are the same temperature going into the core and coming out.

in may i replaced the thermostat but was in a pinch and just got one from NAPA. Is it possible that I got the wrong one?

i saw a post on here about getting the thermostat from Ford, but I can't find it. Any help would be great!

 

[Andylad13]

is the engine up to running temp when your not getting heat?? if it is then its not the thermostat, however if its still not heating up in that amount of time, then it would be the thermostat stuck open. but thats highly unlikely if you picked up one recently. did you check it in a pot of boiling water before you put it in??

 

[MIDNIGHT RIDER]

Is the summer-time valve under the hood open ??(of course, this only applies if it has a valve.)


When you FEEL of the heater-hoses are both HOT ??


When is the last time the blower was pulled out and the rat's-nest removed ??

 

[oldmisterbill]

Is that year one with a vacume operated heater control.My 91 has lost heat twice-both times it was a bad vacum line funny it was right under the heater core. If I understood right you said the temp was the same in and out of the heater hoses(Hot I am assuming)

 

[Brimmstone]

When I was still living in Ohio I had to put a piece of cardboard over about 3/4 of my radiator face just to get some heat in the truck. The radiators in our trucks are extremely good at cooling the engines down. If I remember capacity correctly the radiators on our trucks hold over three gallons of antifreeze by themselves. Another issue could be are you running your antifreeze at the correct mixture? I had a car years ago that no one could figure out why it would never blow any heat inside the car but it never over heated. It was finally found that the customer had changed his own antifreeze and put in straight antifreeze.

 

[osus86diesel]

the hoses are only warm, you can grab them with bare hands and not worry about being burnt.

the blower is working, because it blows luke warm air out...

what/where is the valve?

i may just try the card board/ seed bag trick first, dad always did that to his.

 

[LCAM-01XA]

Jess, try tracing the hoses from the heater to the engine - if you just see straight hose, and nothing else plumbed in, you have no heater core shutoff valves. Here's what my shutoff valve looks like, it's the thingie in the lower left corner of the picture:

You must be registered for see images attach

By the way I have a locked fan (handles traffic jams in 90F just fine) and even with that I do get to decent temperature, so a thermostat stuck open is definitely something you may wanna look into.

 

[MIDNIGHT RIDER]

The heater-core could be stopped up, thus the coolant is not circulating, hence the hoses not being hot.

Remove the hoses and flush through the core both directions with a water-hose; see if a bunch of rusty crud comes out.


My old 6.9 would always heat right up and run you out of the cab.

It takes the Cummins a lot longer; but, once it gets there, there is plenty of heat.

 

[ghunt]

I've always been told that warm heater hoses on a hot engine are a sure sign of a plugged heater core.

 

[LCAM-01XA]

Yeah, pretty much - basically the temperature of the heater core hoses should be about the same as the one of the upper radiator hose, if the big one is so hot you can't hold it so should be the small ones too.

Also Jess, you're in OH, y'all get as cold weather as we do up here - have you thought of a grille blanket? I just put one on my truck today, it don't screw up normal cooling like the cardboard sometimes does, but it sure helps against windchill.

 

[NJGearhead666]

I had a mustang with a cloged up heater core i pulled the hoses off and put some kerosene in it let it sit a while and flushed it out all sorts of gunk and stuff came out. heat worked great after that

 

[jimraelee]

Pull off the lower heater hose off the core, you should see lots lots coolant flowing out, if not then you do have a blockage. Oh and once you see good flow out ta the core, put it back on.

 

[CDX825]

And I quote cdnsarguy from TDS
CAUTION:
The specified/required thermostat does not contain an internal bypass, since the bypass is located in the cylinder block. Whenever the thermostat is replaced, it is mandatory that only Motorcraft E5TZ-8575-C or Navistar 1807974C94 thermostat be installed.

 

[osus86diesel]

And I quote cdnsarguy from TDS
CAUTION:
The specified/required thermostat does not contain an internal bypass, since the bypass is located in the cylinder block. Whenever the thermostat is replaced, it is mandatory that only Motorcraft E5TZ-8575-C or Navistar 1807974C94 thermostat be installed.

Thanks, that was the information I was diggin for!

 

[CDX825]

No problem! I just ordered one from Ford a few weeks ago. It was $25.50 and included a gasket. I'm just now geting around to putting it in. Also going to be adding a external block heater and a coolant filter. I'm just hoping after this I wont need cardboard in front of the radiator to get warm :lol: