'89 CRX. Went to friends house, heater working. Left friends house 8 hours later, heater not working. Had professional flush out cooling system. I went back and flushed out heater core myself. New thermostat. Heater core not leaking. Both hoses getting hot. I am getting maybe a five degree change in temperature when I turn on heater. Am I going to have to break down and change the core out? Any help would be greatly appreciated.

 

Check to see if the heater control valve is opening when you turn the heater control open. Try it fully cycled to one direction with the cable off. if no heat then try it full cycled to the other direction. if that valve is closed it will not flow water thru the heater core. BTW that valve is on the firewall passenger side just behind the thermostat housing. A hose runs from the thermostat to the valve.


[Modified by tpr, 3:39 PM 12/20/2002]

 

I had the same problem right after my system was flushed but on top of that my water pump started to leak also. I changed my thermostat to see if that would help and also used an air compressor to blow some air through the heater core since a shops aid it was bad well after I did all that and rebled it everything was fine??!! Even the water pump stopped leaking but I am once again having the problem with little heat?? Is it possibly that my water pumpo doesn thave enough pressure to push through the system?? Oh and before you go and buy a new heater core try bl;owwing some air through it and see if that helps??

 

Heater valve works fine, bottom hose gets very warm only when I open valve.

 

Thanks for the help guys. It turns out the cable that controls the air flap (?) is not closing off the cold air completely.