1996 taurus 3.0 2 valve .I need to flush heater core.?

Question

i have read thet you need to put heat on full when filling after flushing? doesn`t the coolant flow through the core at all times? is there some control valve or such that controls the coolant flow through the heater core itself? both inlet and outlet hoses are hot? when i turn on heat i only get heat for 15- 20 seconds then lukewarm. and temp gauge starts to lower visibly!!

the blend door motor/mechanism rotates the shaft 90%

just replaced themostat 197degree oem.temp. starts out in just above middle of normal range and will drop say a 1/8 of range, not much but enough to give nme lukewarm heat!

there is a plastic tee attached to the hose off the water pump, it also goes to the heater core and to the themostat housing. is there a diverter in the plastic tee?

i put hose into upper outlet on heater core and blew through it . i can blow through it with some resistance,but water pump must be much stonger. i can also blow water thru it. is core clogged or what??

Answer 1

if their is air in the core the only way to get it out is to turn on the heater as far as flushing yes you need to turn it on heat to get the flow through it

Answer 2

If your still in the process of refilling the coolant then keep going you need your engine full in order to have coolant circulating in the heater core. Temp gauge drops when thermostat opens. if system has no air and full of coolant, vehicle is running at 195 f check heater hoses for temp on inlet and outlet. If satisfied, and still no heat in car, then start looking at the blend door. This would allow fresh air to by pass heater core.

Answer 3

Engine temperature will drop SLIGHTLY with Heat on, but shouildn't fall very far. You didn't say where the temperature started at, but it sounds like either the wrong or a stuck open thermostat