I have a 2001 expedition and the heat has started acting up. I've changed the thermostat, flushed the coolant, and still minimal heat. The blower runs like it should but the heat coming out is lukewarm at best. The hose from the engine o the heater core is hot but the outlet hose is just slightly warm. Anyone ever had this issue and if so please advise on how to remedy this. My wife's gonna take my 250 from me if I don't get the heater fixed.