Got some issues with the amount of heat being delivered to the cabin. With 30 deg outside, I'm seeing about 110deg at the dash vent. Just doesn't seem hot enough. Suspect the heater core is partially plugged.
Could someone with a good heater please check the temperature at the dash vent with full heat and fan on high? Also please give the outside temp at same time.
Thanks Frank

 

I checked my heat today. Outside temp is around 30 -32 F. Temp coming from centre defrost is about 110 degrees and from the vent left of glove box is around 120 degrees. As I drive for about 30 minutes both the temperatures will increase about 10 more degrees with sun shining outside . I think the heat gain thru the glass and materials warming up in the cab are at least part of the cause of the temperature rise. However if I am doing freeway speeds it will drop back to the original numbers I posted. While I am comfortable I feel it could be better. I am going to try a few things and I will let you know of my findings.

 

We have had a cold snap lately here in the south ... didn't feel my heater was putting out like it should. Outside temps were in the 40's. I wonder if recirculating would help ... I don't think I had recirculate on ... wonder if there is a setting for it with heat and A/C compressor off.

 

Nope, the only way to get the recirc to work without the A/C being on is to run a new manifold vacuum line to the actuator for the recirc door. I suppose you could just unplug the electrical connection at the a/c clutch, that would work too.

 

Thanks Mississauga for checking your temps. Sounds like I'm going to have to tear mine apart. Either the blend door is not shutting all the way or the heater core is partially plugged. Sure wish I had know about this a couple weeks ago when we had record warm weather. Could have done it in the drive instead of dribbling coolant in the garage. On the bright side, a couple months ago I installed a hanging gas heater so other than a cold floor, the garage is very comfy in cold weather.
I know someone has to have a heater than about frys them if they don't turn it down. Wonder what kind of vent temps they are seeing?
Thanks Frank

 

I checke dthe thermometer in mine coming back from Nissan (at 2 in the morning) and it read 105 degrees out of the inboard vent, drivers side; 108 inboard passenger side. I actually had to turn my heat down due to it getting too hot inside the cabin. Outside temp is 21 degrees now.

 

Thanks for the info KDPate. Those numbers are not very far from mine. Now I am really confused. Oh well getting to be my normal state.
Thanks Frank

 

When I checked... I found 20 deg difference between the thermometers I had. I picked the one I liked the readings on & gave the other one to a friend of mine.

 

Today with the temperature around 30-32 F and sunny outside I tried something to help increase the heat. There is a door that controls the amount of air being brought into the cab from the outside, called the outside recircutating air door. I removed the vacuum line from the motor and plugged it . This motor controls the re circ door which is in the enginge compartment above the heater blower motor. I wired the door so so it stayed in the half closed position. By doing this I raised the temperatures by at least 10 degrees from my earlier post. The air flow is a little stronger coming out of the defrost vents also. Air is hottest when the fan speed is 2nd from the fastest . Last year I closed this same door all the way and I ran into some fogging problems on the inside of the glass. Could it be a build up the moist warm air from the occupants when exhaling hitting the cold interior of the surface of the glass causing this? With the door open it seems that this air exchange solves this problem . I think with the door partially closed and some experimentation you could find the sweet spot for max heat and no fogging of the interior glass.

 

Thanks for the idea. I'll take a look at it.
Today I drove my Grand Marquis. Checked the vent temps in it. It quickly produced 140 deg air and after driving in traffic it got to around 150deg. Outside temps were about 34. Actually I had to roll the window down to keep from roasting while I was seeing how hot it would actually get.
It is a lot newer, but the passenger compartment is a lot bigger too. Probably not a good comparrison vehicle, but it is available.

 

I had a problem with the cable that controls the blend door. Behind the glove box, the end of the cable sleeve attaches to a clip and is held in place by friction. Mine comes off the clip occasionally making the blend door non-functional.

Usually it prevented the AC from cooling properly.

 

I have an 87 F150 I6, without AC, this morning I went to change the switch from Panel to Defrost, and heard a little crack from behind the heater control face-plate. Now I can't change to anything other than the floor, which is where the setting was when I heard the snap. Am I in for sub-zero junkyard work? or is there some temporary patch I can do to hold me over till spring?

The Admiral

 

my heat gets real hot during normal conditions, but as the outside temp goes down, so does the heat temp. I think it is the blend door. Is there anyway i can rig this door to close? or at least fix it. What could be the problems with the door causing it to not work?

 

Alrighty!! I now have a heater that will burn toes right off my feet.
I had 2 problems. A 2.5 inch deck screw was stuck in the blend door and keeing it from closing completly. The heater core had leaked in the past and evidently got a dose or two of aluminum flake stop leak. This at least partialy plugged the heater core.
A new core from Auto Zone, $20, about 30 minutes work, and I got a hot one. Dash vent temps before the work were around 110-120 with outside air temps of 35-40. Now at 40 outside, I have 160+ at the dash vent at idle. My son promptly borrowed it as soon as I shut the hood, so I won't get a chance to drive it for a few days, looking forward to quicker warm up and defrosting.
Thanks For everyones input.
Frank

 

Sounds great. There has been quite a few instances of things blocking up the blend door posted on this site.