The ECM monitors the thermostat every time you start the engine and compares the ECT readings to the RCT readings to ensure the thermostat is operating within design parameters. NOTE: GM recommends you DO NOT replace the engine coolant thermostat unless you find a thermostat related trouble code. The ECM makes the determination whether pellet heating should be done by the engine coolant or by the heater, depending on load conditions The thermostat should be fully open at 243☏. When 12V current is applied, the thermostat begins to open at 176☏. When operating properly, the thermostat begins to open with by itself when engine coolant reaches 217☏. The pulsed current is determined by the ECM. The wax in the pellet can be heated by the engine coolant OR, by applying a pulsed current to the heater located inside the pellet. The newer electric thermostats are designed to fix that problem.
2013 CHEVY SONIC ENGINE DIAGRAM FULL
So car makers added a heater to the wax pellet to force it to open faster to allow full coolant flow and prevent overheating.
![2013 chevy sonic engine diagram 2013 chevy sonic engine diagram](https://dz310nzuyimx0.cloudfront.net/strapr1/e941a205019891fa1cdd9ee05df6dc66/cb2771f3e8c1b75ec4286689e8729f06.png)
Traditional wax pellet thermostats are slow to respond to temperature change in the engine coolant.
![2013 chevy sonic engine diagram 2013 chevy sonic engine diagram](https://i.ebayimg.com/images/g/TzcAAOSwor1advAY/s-l400.jpg)
As a result, the engine doesn’t reach full operating temperature as quickly and may not provide enough passenger compartment heat. In addition, short trip driving and low heat generation by the engine may prevent the thermostat from opening as quickly. Because the engines are smaller, they may not generate the same amount of heat at idle as a larger or older engine. To get the power of a larger engine, but with increased MPG. Electric thermostat and housing used on small engines