2003 Dodge Ram 1500 4.7 4WD

• It will not blow hot air unless I am going highway speeds. when I slow down it blows cold
• Heater fan is working normally

The heater blows cold air for much longer than it used to after starting vehicle

Anyone have any ideas? I searched but didn't seem to find anything quite like this.

 

Both heater hoses hot? Both radiator hose hot?

 

Sounds like the 'stat is sticking open.

 

Both heater hoses were cold if I didn't get to highway speeds, hot if I did.

Rookie mistake. I was a gallon low on coolant. This started happening shortly after a trip to get the vevicle serviced, oil change, top off fluids etc.

They tried talking me into a radiator flush but I didn't let them do it.

No leaks before, no leaks now. HMMMM.

 

Glad it was simple.