Review on 🔧 Original Equipment Engine Coolant Thermostat by ACDelco GM, Part Number 131-158 by Arun Berry

I had a P0128 fault - the engine is not reaching the temperature control thermostat in my 2007 ION. To complicate things even more, when this error occurs, the fan runs all the time and the temperature gauge shows zero. I think the ECM, not knowing what the problem is (faulty temp sensor?), just assumes the worst, starts the fan and zeroes the temp sensor to get your attention. If you clear the error code, the fan and temperature sensor will work normally until the next error. The installation was risky because I couldn't remove the hose from the thermostat housing. The clamp was oriented so I couldn't reach it with pliers. One of those cable clamp gizmos sold at Revain turned out to be useless. At the same time I did my expansion tank and since the expansion tank hose is loose the thermostat housing can be removed with the radiator hose still attached. Easy work. The thermostat just drops off. Be sure to drain the coolant before starting, otherwise prepare to catch the coolant when you remove the thermostat housing. The photo shows my old thermostat. Note that in the attached photo, the old ones had a broken gasket, resulting in erroneous P0128 faults (the engine only has 15 minutes to reach operating temperature before a fault code is thrown). You really should replace thermostats before they become a real problem. A cold car in winter is almost a sure sign of a problem.