Currently don't have any heat at all. It used to work at idle after startup, then shut off after a minute or two of driving. The blower still works, just pushes cold air. I've flushed the radiator several times over the last 2 years to no avail. Thinking maybe thermostat or heater core, but I'd like to hear some thoughts from more experienced minds, thanks.

 

Could be anything you describe. It also might be the blend door actuator not directing heat from the core. Is the air blowing out to the floor?

 

See if both heater hoses are equally hot. If one is hotter than the other than you, probably have a clogged heater core. If they are both hot than it could be the blend door actuator as described above.