Engine Overheating Found the thermostat stuck closed

Are you saying the vehicle is overheating, just according to the gauge on the dash? That may just be a false reading, of course we cant assume, back to your question, a couple of things that may cause overheating of the coolant, can be incorrect dilution of the coolant, you must use fifty/fifty, a bad radiator cap, will cause extra heating, a semi clogged radiator. Is another, what Iam thinking may be a possibility as to why the gauge is reading high, is the engine coolant temperature sensor, if that is faulty it will give erratic and false readings. Also you will need to make sure that your radiator fan isnt bad. Check to see if it comes on, one way to check if it is working, is to hardwire it directly to the battery.
Any more questions feel free.
Jody