My thermastat on my Kia Sorento is movining up and down. Do I need a new Thermastat, Water Pump or Radiator

the gauge you're looking at is called a "temperature gauge"- the thermostat is on your engine and controls the engine temperature- it is impossible to tell what is causing your car to overheat- it could be something as easy as low coolant level- check your coolant and add some if necessary- do NOT open the radiator cap when it's hot- I would suggest you take your car to a good mechanic and have the whole cooling system checked-

Showed smoke actually carbon from rear exhaust pipe, car runs hot,( not Been the road for two days, leaving yard, the temp. Gauge go up Closer to middle symbol. Told to put on heat. Change in weather., Knocks down the gauge. ??