No Heat on 2004 Hyundai Tiburon

Hi Guys My Tiburon heat stopped working. Everything sounds as if it's working properly but no heat. I have the 3 knobs controller. When I'm under the dash and I change the temp control I can see it working properly. When I test the of the 2 water lines coming in and out of the core they are approx. 120 degrees. This happened all of a suddon not gradual. The only thing out of the ordinary is that the heater normally worked really good and I mean very hot so I was thinking something may have melted. I'm considering ripping the dash out and getting to the flap door and see what's goin on. When I rotate the knob and change the temp, the electric motor turns and you can hear the flap door open and close and the sound and volume of the air changes. It's as if the heater core is cold, that makes no sense. Please help.

by in La Mesa, CA on December 01, 2010
2 answers 4 comments
ANSWER by on December 01, 2010
120 degrees is nowhere near hot enough to generate heat for your interior. Your heater core temperature should be more like 190 degrees with the engine at operating temperature. Check for a possible thermostat sticking open.
COMMENT by on December 01, 2010
Hi Dave That temp I took was on the outside of the hose going in and out of the core. The inside i would have to assume would be between 180 and 200. Is there some sort of diverter behind the firewall that doesn't allow the coolent to reach the core?
COMMENT by on December 02, 2010
No...but I still feel like your symptom is related to an engine that is not getting hot enough. You have done an otherwise decent job of trying to eliminate other components from the potential failure list.
COMMENT by on December 02, 2010
My temp shows normal and the fans kick on and off on a regular basis. I'll change the thermistat to eliminat that and try to see if i'm accually getting flow through the core. Thanks Dave, I'll update as soon as I do that.
ANSWER by on December 02, 2010
The problem you have described is most likely a thermostat sticking open and/or a plugged heater core that may need replacement.
COMMENT by on December 02, 2010
My temp shows normal and the fans kick on and off on a regular basis. I'll change the thermistat to eliminat that and try to see if i'm accually getting flow through the core. Thanks, I'll update as soon as I do that.
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