No heat issues 2000 Echo

[joshz]

2000 Echo, I noticed the other day the heat was half as warm as it should be. The blower is still moving air the same as it always has. The upper radiator hose is hot, the lower is cold. About the same temp as the air in the 30's. The line going in to the heater core and coming out are both really warm. I thought is was the thermostat so I had it replaced to day by a local shop who does good work. The problem persists with the same symptoms. The car has yet to have the high temp light come on. Any ideas?

[nevada]

check the blend door.
if both hoses are hot, then water is getting into the heater core.