Ok folks here's my situation:
My heat only seems to get nice and hot when it's not really really cold outside. I've monitored this on more than one occasion so I know I'm not going crazy here. I would say if it's 20*(F) and warmer the heat work well, but once it gets in the teens and single digits, my heat is lukewarm at best.

Any ideas??

Here's my specs and my thread:
92 F150, 5.0, 126miles, new heater core < 1yr old, new coolant < 2 yrs old, new lines into heater core < 1 year old.

https://www.f150forum.com/f10/fresh-start-260282/

 

It sounds like it's not getting hot enough. The most likely culprit is usually the thermostat.
It should be a 192.
Besides not keeping you warm, if the motor doesn't get hot enough it stays in open loop (computer's warm up program) and drinks a lot of extra fuel.

 

You should put all the truck's details into your signature:
https://www.f150forum.com/profile.php?do=editsignature


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2 year-old coolant needs to be changed, but it won't prevent the heat from working. SORRY - RONG: 3 years!

Have you ever cleaned the evaporator core? It takes a little effort to get it out of the box beside the intake plenum, but you don't have to discharge the refrigerant.


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Likewise, cleaning the blower will increase airflow. But be gentle - the original plastic squirrel cage is much more efficient but much more fragile (at this age) than the aftermarket steel replacement.


(phone app link)

 

I have a 192 thermostat and it regularly gets to halfway on the gauge. I'll try the evaporator core and blower as I haven't touched those yet. I also didn't realize coolant needs changed every 2 years?? Thanks for the suggestions I def would not have thought of those.

 

Whoops...

 

Suggest to check that your temperature blend door is sealing off properly...

 

Yep. Read this & the NEXT 2:


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this is all good stuff- i'll dig into this more this weekend. thanks again all.