I have a 2004 f150 5.4L I noticed while driving home tonight my temp dropped below normal heat was hot them luke warm it's 5 degress out. Got ho.e checked the upper hose and heater core hoses both are hot lower hose is cold and the coolant tank is ice cold as well. Not sure if it's the radiator or thermostat or water pump. Any advise is greatly appreciated thank you

 

If the top heater core hose is hot and the lower is cold ... that means you have no circulation through the heater core..

 

Did the temp on the gauge drop? If so it sounds like a thermostat.

 

Yes the temp on the gauge dropped. The goes back up then dropped again

 

Sounds like a thermostat. Temporarily I'd put a piece of cardboard in front of half the radiator. That should warm it up enough for the heater to work but keep an eye on your gauge. At 5 degrees there should be no problem.

 

Ok thank you I'll change it out this weekend. Do you burp the system the same way as a normal radiator

 

My 2006 doesn't have a radiator cap so I think all of the air will work it's way up to the reservoir. Or whatever they call it. In the Army we called them 'surge tanks'. :-)

 

My 04 has the same tank as your 06. Thank you for your help greatly appreciate it

 

On my Jeep I use a 'Winter Front'. It helps keep me toasty here in Montana.