QuestionQUESTION: I have had a heater problem for a while. I replaced the water pump. Checked the programmer and it seems to be correct. But, although it blows hot at first something changes and all of the sudden it blows cold and never warms up.
ANSWER: When the engine is running and you are at normal operating temp is the gage on the dash reading normal engine temp ?
You may have either a partially plugged heater core and or a fault in the programmer.
Remove the glove box liner and you will see a threaded metal rod attached to a plastic clip. With the heat on full heat the metal arm should be towards you and should not move inward towards the firewall. If it does, You have a problem with the programmer.
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QUESTION: Yes it reads from 199 to 212. The programmer seems to be in the correct position and moves as I go from AC to Heat. The correct vents are blowing air but, it is the wrong temperature. How can I tell if my heater core is blocked or the valve or thermostat is working correctly?
AnswerYour engine temp is OK. When in the heat mode there should be NO VACUMM to the vacuum line going to the heater valve. Simply unplug it and see if the heat gets better. Don't forget to plug it back in.
As far as telling if the heater core is partially blocked check both heater hoses going to the heater core. One should be EXTREMLY hot and the other slightly cooler. If they are. Replace the heater core.
You can also test to see if the programmer is opening the heater door all the way by putting the heater on full heat and waiting until the threaded metal rod stops moving towards you, Wait a minimum of 3 minutes, and then disconnect the metal rod from the plastic clip and see if you can pull the threaded rod towards you any further and if you can, See if you get more heat. If you do get more heat, snap he rod back into the plastic clip as you hold it all the way towards you.
If this does NOT work, replace the heater core.
