I was running water and super flush, with the new thermostat. Driving on turnpike the temp gauge started to rise above half. I drained the super flush and water out, flushed again, hecked thermostat to insure it wasn't stuck and it wasn't, but the last one was stuck and the DEXCOOL was in it. They have different silicates in the different coolants and DEXCOOL is mainly gm vehicles. I'm thinking the recent over heating was just from the water boiling and evaporating. I put the new coolant in after I flushed out the super flush and drove around city driving stop and go. No problems since and both fans work on the radiator. I drove for a total of an hour stop and go and stopping at two locations with the car off for roughly 10-15 mins per location. Like I said no problems at all for now but I don't wanna risk another $250 tow. Maybe coolant temp sensor possibly?