The heater only heats when the engine is running above idial. I have change
the thermostat. and Flushed the cooling system. I have to set in the car
and run the engine at high idial for 10 mins. to defrost the windows. Once
I start driving, it warms up ok.
Thank you for your help.
Sorry, not enough info. Is the blower coming on and the fan speed switch
works? Temperature control dial works? Engine cooling properly? How fast
do you have to spin the engine for it to "defrost or heat?" Is the
problem that there is plenty of air, just not hot enough or is the air flow
not sufficient and the air that IS coming out is hot???? Does the air
smell of coolant to indicate the heater core may be leaking?
Defrost on that car uses the air conditioning compressor to super cool the air to aid in defrosting. TOTALLY different. Sounds like you dont have a "heater problem," you possibly have a problem with the a/c / heater box assy under the dash or some component thereof. You might have a vacuum motor issue causing little to no vacuum to be supplied to the blend air doors, etc etc etc and the list goes on. Try explaining the problem more in depth and perhaps I can give you more indepth help.
Sorry about the lack of info.
The blower operates fine. I get plenty of air from the verious discharge ports. The engine dosen't overheat and the gage showes low temp when at idle. when the engine speed is increased to around 1500 to 2000 RPM the temp will begin to increase. Thank you for your help.