I have a 2012 T&C that is overcooling. When driving down the road at 60mph this engine temperature will only reach 174-176. You can stop and the upper radiator hose and thermostat is Cool. I have taken to the local Chrysler deal and they have change thermostat twice. They are now telling there is nothing wrong, because they have a second 2012 doing the same thing. I was there and took out a 2015 T&C which ran down the road at 192. I have look with the dealer and read that operating temp on both the 2012 and 2015 is 192 to 199. I have also looked with them and compared that the cooling system on the 2012 and 2015 are the same from Radiator, Thermostat, and water pump. I have block off the heater line to make sure there wasn't a problem there. When idling my 2012 you can feel the thermostat open around 190 and the upper hose get hot. I am trying now to figure out how the 3.6L engine is bypassing the coolant in it system to keep the water pump from cavitating. At the same time because of the temperature drop in the engine it is running a richer air/fuel mixture and fuel mileage has drop to 15-16 mpg. I block off the air flow over the radiator and test. I can than get the engine to 190 and my fuel mileage comes back to 24-30, So I know that the engine is not suppose to operator at 176. Looking for and ideas or more ways to trouble shot.