Overheating

When you put the thermostat in the cooling system needs to be purged from air pockets while refilling.

Put the thermostat back in (make sure it is in the correct orientation) and purge the air from the system as "Rowefast" suggests.

Thanks i will give it another shot

How do u purge it? Is there a valve or a special tool? Bare with me please i kno very little about car lol

Ok so you have the thermostat in correctly? Fill radiator with 50/50 mix coolant. Leave the radiator cap off and the heater settings on hot. Start the engine and let it warm up to operating temperature. The coolant may spill out the radiator at first until the thermostat opens, then you will see the coolant level in the radiator go down, when it does fill with coolant again. Keep the motor running and the cap off and let the thermostat open and close a few times adding coolant as necessary. You will notice circulation each time the thermostat opens. When satisfied that it is full then put the radiator cap back on, then you can turn the vehicle off.

My question is i have a 2003 ford expedition i replace the thermostat replaced the water pump put a cluch fan it it got a pressure check and its still overheating

What is the problem

Make sure the cooling system is purge of air.

Would a thermostat for an 02 expedition work on an 03