P0126 Mazda -

Question

Changed the thermostat and the temp comes up and heat works only under power. When its idling the heat goes away. What is the cause, i tried removing the air from the system and i believe its out but not sure.....will this cause it or should i try something else?

Answer 1

you will have to run the heater with the A/C off, for 10min then drive the car for 5miles or so with the heater on to remove the air from the system(assuming the coolant is already full if not you will get more air in the system)

if problem is still there coolant temp sensor might be bad