I have a 2006 Jeep Liberty 3.7L that has a temperature gauge on the dash that reads an overheat when driving. The oil looks normal, there is no white smoke, no bubbling from reservoir. I have replaced the following:
Coolant Temperature Sensor
Coolant Reservoir Tank
I am not leaking any coolant and the reservoir level has been fine. I have let the vehicle idle for 20+minutes, with no overheat. When I drive it around, the temperature gauge will read an overheat. When I stop the car and pop the hood, the engine is not overheated and both rubber hoses to/from radiator are flowing the coolant. The only thing that will bring the gauge down is turning on the heater full blast. Could this be the gauge itself being bad? Could it be a short in a wire somewhere? I had thought maybe a head gasket, but have no symptoms of a head gasket. Any ideas are welcome as this is getting more expensive than its worth to troubleshoot this vehicle.