1997 heater
 

the car wont heat up, i think it might be a heater control valve problem, any suggestions?

how long have you been trying to heat it up?yeah, I think its the control valve...

short term: i drive around for like 20 mins, and its not heated

Long Term: It just happened Recently, could be cold weather

the engine itself heats up fine, and the dial is in the middle, and when i turn on the heat, its warm then quickly cools off...

What happens with the control is turned to full heat?

it gets hot then quickly cools in like 2 seconds...

If this is a manual climate control system check the following:

That the heater core is not partially plugged with debris from the coolant system. You can remove the heater core hoses and apply water from a garden hose to flush the system out.

The heater valve is working OK. If the manual control system the valve moves in response to the control knob by a cable. You can watch the valve arm move as someone turns the knob. Make sure the valve is opening and closing when the knob is turned.

On occasion a bad thermostat will cause heater problems.

If the engine temp gauge moves to normal but no heat would be looking at the valve or a blocked heater core.

THe doors inside the dash which control airflow have to be in the right position to get heat, they are vacuum operated and controlled by the "other" dash switch. If your coolant has been changed regularly and looks good (not dark rusty brown) the heater core is probably OK but still worth testing. A new thermostat is also a good idea. If the car is an I-4 the thermostat cover is right in front of you at the end of the top radiator hose.