Hello to everyone, this is a friends car that Im working on which initially had no heat with a check engine light on. Checking the codes returned a thermostat code. Hoses weren't getting hot and I suspected a thermostat issue before reading codes. Reset the codes and thermostat code returned once again almost immediately. I then changed the thermostat today and reset the code and code has not returned after a long drive. Curious how the PCM detects a thermostat issue without any sensors on the thermostat itself. Im guessing in and out temp sensors?

Regardless of resolving the above, the heat was still blowing cold, I then checked the valve under the hood by removing the cable and valve and it did open and functioned normally when turning by hand, currently in the open position and still no heat. Not sure what controls this cable but it does not move when going from hot to cold or vise versa but again its in the open position. I then went to the actuator for the blending door and that functions normally as well. After bleeding the car on a hill, I finally got some heat to come out only on the right side and now I suspect that this is an air issue in the heater core. Is bleeding this model a 2007 with a 2.4l known to be problematic or have special procedures? I plan on getting a coolant bleeding kit and any input is appreciated. Currently have it with the radiator cap off and hopefully it burps overnight.

 

Had to add coolant this morning and wondering if this could be a head gasket issue. Temp is slightly on the low side and radiator never pressurizes. Will see how often we need to add.

 

Could you at least share the code #?