2001 F150 4.6L 4x2 XLT 2 door reg cab short bed; 165K miles.

No heat issue. Replaced thermostat. Changed out reducer. blew out core with air. Still almost no heat. Just a little heat. The colder it is out, the less heat. More heat when warmer. The front vents are cooler than the side vents. AC is fine. Fan is fine.

Reading posts seems like maybe air blend door issue?

Where is it, how do you get to it, how do you fix it.

Ideas?

Thanks.

 

Do you have the analog AC unit, or the digital?

 

Mine had similar issue flush te heater core and got to be how you describe with more heat when hotter out, eventually figured out mine will only get hot and stay hot on panel every thing else engages ac compressor on mine

 

The most common cause of your problem is low coolant level. Other could be a bad water pump. If your system was rusty in the past, the bad fluid could have caused your impellers to rust and desinagrate on your water pump and thus it does not work as effective as it should. To check, squeeze the upper heater hose with engine running. release the heater hose and listen for SQUISH and the hose should quickly return to shape.

After you do that, try adding more coolant. If it takes the coolant, try the test again. If not a good squish, it doesn't return to normal and, rust previously in the system, you have a water pump issue.

 

blend door...can you hear it change positions ??

 

Analog AC unit - manual controls

 

Mine is not getting hot on Panel either...but it is strange that side vents are a little bit warmer than the front vents. My full on hot is luke warm at best and on cold days it does not keep up at all.

 

Water pump....seems that the truck run hot. It runs cool. It ran too cool and then I changed the thermostat. Also replaced fluid at last oil change with fresh. I will try the sqeeze test.

 

No. Where exactly is the blend door - how do I get to it?

 

Take out your glove box there is a peice of plastic behind it, cut it out and you'll see a black box you can cut into just inside is your blend door, just be sure to seal it all back up good, or you can take the whole dash apart if you are opposed to cutting