the check engine is lit/P0128 ? HAVEN'T TURNED A WRENCH in YEARS. Is it simple to r/r a thermostat in this car.
Are there special procedural steps (to prevent air from being trapped in the block?) any advice gladly accepted

 

Change the thermostat and sensor.
It is straight foward.
The Air will purge by itself.

 

Tech- Could this code be thrown if it is just the sensor that is bad? How can you tell if the car needs the thermostat as well?A friend of mine has the same car and code, and I am trying to determine what needs to be replaced. Thanks!!

 

You will know if the thermostat is bad once you open it.
Also you could boil water and set the thermostat into the water and make sure it opens.

 

My buddy took it to the dealer to have it repaired. They said it was the thermostat. $125 total. I guessed it would be asensor, since it threw a code.

I still can't figure out how it could be the thermostat when it wasn't overheating or having difficulty warming the interior (that is, either stuck open or stuck closed).

 

Most of the time it breaks. It is just enough to throw the code but not really affect how it runs.