Engine over heating

Does the fan come on when the engine reaches operating temperature?

why not consider your radiator cap ( if the car has one, mine doesn't )? Engine coolant sensor??

First thing's first, check to make sure your cooling system is full. Also, when the coolant was refilled after changing the water pump and thermostat, was it bled properly? Improper bleeding could cause overheating. Also, when the car begins to overheat, shut the engine off IMMEDIATELY. These all-aluminum engines will suffer severe, permanent damage from overheating. That extra 30 seconds could cost you an engine... which is way more expensive than the repair to the cooling system which should fix the root issue.