I have an '03 F-150. Yesterday it overheated within 2 miles from my home. Parked it immediately. Never saw any visible signs of water leaks (hoses/coonections). Changed the thermostat and drove about 10 miles without any signs of overheating. Got in this morning and within 5 miles it overheated again. Parked immediately. Water pump???? or other issue?

 

Is there fluid in the overflow?

If not, there is more than likely a leak somewhere. It may be small, but it is somewhere. Add fluid to the overflow/radiator and run it for a while to see if you can find the leak.

 

when you changed the thermo you may have let air in the system