QuestionQUESTION: My heater is blowing only cool air. The core does not appear to be leaking and water level is full. I have just replaced the water pump. I have been told that it could have a vaccume leak but am not sure?
ANSWER: Hi Tim,
Feel the temp of the two hoses that go through the firewall to the heater core. They should be similarly hot.
If one is hot and the other cool, then you have either air trapped in the heater core which you can get rid of by draining and collecting the coolant down to the level of the core, then refilling the system OR you have a clogged heater core which you might remedy by back flushing through the core with a garden hose from the cold side attachment point to the hot side attachment point of the core.
If the hoses are both hot, then the air door that deflects the air either to the heater core or the ac evaporator core (or a mix of the two) is stuck or not reponding to your request for warm air.
Let me know what you find and we can go from there.
Roland
PS Please 'rate' my answer, and where you see the question about a nomination to be 'volunteer of the month' please consider a 'yes' answer. Thank you.
---------- FOLLOW-UP ----------
QUESTION: Roland
It may be a day or so before I am able to Check this. If I find the hoses are both hot, how do I unstick the door?
AnswerHi Tim,
There is an electrical actuator for that door which may have failed, or the door may be binding up. In fact there is a calibration/self-diagnostic that can be run which might ID such a problem*.
In any case, the actuator and 'blend' door mating spline are located on the driver's end panel of the underdash distribution system. You would access it via removing the under steering column panel on the driver side, and the ABS module if you have that feature, in order to see/reach the various actuators.
But first check out the hose temps after driving far enough to fully warm up the cooling system.
Roland
PS If you would be so kind as to 'rate' my answer I would be most appreciative.
*To try the test:
Engine must be running and warmed up
Set blower on high
Set mode to panel
Open all air outlets
Set temp to full cold
Depress wash and rear wiper buttons simultaneously for 5 seconds, when all LED's light, release the buttons.
Various tests will occur for the next two minutes and various LED's will light. Let me know what LED's are doing when it is all over.
This may correct the problem,
