Heater sometimes will blow cold air. Cycling the heater temperature control does not help.
Then, spontanieously, and suddenly it will start blowing warm air.

On other occasions, the system works completely normally.

Where is the hot water control valve on an RX-7 (1987)?

How does the control lever actuate the water control valve? (It doesn't feel like a cable control; and the Chilton manual sheds no light on the subject.)

Any thoughts?

rhbohl@aol.com

 

I don't think your RX7 has a heater control valve. Coolant is always running thru the heater core and temperature is adjusted by how much of the airflow is allowed thru the core by the blend motor. Try this. When the heater is operating normally, listen carfully for the sound of a motor running as you move the temp control **** back and forth. Motor is located in the center of the dash by the instrument cluster so listen in that area. May even need to have key on with engine off to hear. Now when it stops working, again listen for the motor sound. If no motor noise is heard then is a very good probability that the heater control head is failing. The motor is the one that moves the temperature control door in the heater box.