Hey guys, just want to run a quick issue by all the experts. I'm having a heat issue in the 1993 F-350. Here's the situation:

1. I had no heat after the truck reaches normal operating temperature, so I put a heater core in it.

2. Still no appreciable heat, just lukewarm air. When the selector is on "Vent" the vent registers 81 degrees on high blower (at idle then it gets cool while driving). When on defrost, the air coming out is cool on high (didn't take temp). When the selector is on Floor, air comes out lukewarm to cool. When on Mix, comes out weak, but lukewarm to cool. When on A/C comes out warm at idle, but less cool while driving.

3. Both heater hoses are hot when the truck is at normal operating temperature (same temperature by feel and I can hold my hand on them for as long as I want). The top radiator hose is warm, not hot meaning I can hold my hand around it for as long as I feel like, and the bottom one is cooler at normal operating temperature (at idle). When I squeeze the top radiator hose while the truck is running at normal operating temperature, it's not soft and it's not hard but I can feel pressure.

So, unless I am totally wrong, I think I have a blend door problem:

1. When I select temperature control from cold to hot, I hear nothing (the little dial that has red on the right and blue on the left). When I switch from defrost to mix to floor, I hear things change and the airflow moves to the selected location. When I switch from A/C to Vent I hear something change, like a door. When I got from vent to heat I hear something change like a door and air (vacuum I guess).

Please advise, it's cold haha?

Doc

 

your blend door is located behind your glovebox. remove the glove box and you can see the top of the damper just to the right of the heater core, its cable operated. I had the oppsite problem, heat all year around. turned out the cable came loose on mine.

 

Thanks Country, I saw that little cable when I put the heater core in...I'll go outside and look to the right of the heater core box right now. Can you move that door by hand?

 

I looked and I think that damper is to the left of the core box. I can move it with my hand and it still doesn't cause heat to come out the vents, but the core box is warm, so that's a good start, haha. I also noticed that I did not put that little white cable connection back into the heater core box and it doesn't want to go back into the hole easily. Bummer!!!

 

here heres a video of mine the audio sucks but let me know if you need any other clarfication ill make another video if needed... might have to turn up speakers

 

ok heres the blend doors hot and cold movement

 

ok blend door movemet video and pics


heater core temp and video

 

Thanks guys, it was the blend door, I physically grabbed the cable with my hand and pulled it all the way to the right, heat, hot heat, hehe, man it got hot in that truck!!!

Thanks Vic for all vids and to Country for the insight. Hey, maybe this can be made some kind of IDI temp/heater core sticky or something. You can remove all my babble from it, hate to lose the vids in the old post dungeon.

Doc

 

Here are the results:

Attached is the temp out of vent at idle...it actually rose to over 130 F but that's when I took the picture.

 

Congrats!!!!!!!! Now you can hop in your truck and be nice and comfy lol.... next let's get a remote start put in!!!!!

 

You may be joking but I would really like one. Don't know how that would work with the wait to start deal though and sometimes I have to depress the accelerator a little to start quickly. No issues with cold, it's 26 degrees today and no issues starting at all, EXCEPT FOR THE PRICE OF WAISTED DIESEL FUEL.

 

lol i had a remote start put in my 83 mercedes 300sd turbo diesel.... it worked great keyless enrty like modern times lol loved it