I have a crystler 2013 town and country van. I changed out the thermostat and flushed the coolant. It will start to heat up in park but when you put in gear to drive only maintains heat for 10 miles then the temp gauge will drop until it gets to c then a red l lightning bolt symbol will appear on dash and it only blows cold air. But if I put the car back bbn into park and shut it off and then turn back on and leave in park the car will heat back up. But once in drive it will cool back down and do all over again. Please help.