What should I do to fix car heater after flushing it out

Does a 2000 saturn have a blend door acuator

. Did you reverse flush the heater core by itself?

. Are the heater's inlet and outlet hoses hot, when the engine is at normal operating temperature? If not, phosphate scale (minerals from water) may have built up inside the core. Frequently, people have to allow the core to soak in a solution of CLR and then thoroughly flush it out. Another possibility is that the heater control valve is bad.

Often when flushing a cooling system, the crud that comes out of the radiator and motor get stuck in the heater core. If one hose is hot, and not the other, that is probably the case. Remove the hoses, and put something like your garden hose on the side that was cooler, and try to back flush the heater core. Be careful not to get burned, and make sure to disconnect both hoses so that the crud doesn't blow back into the motor. Also low coolant, and an air pocket in the motor can cause this problem.