I have replaced the water pump, fan, raydeateher cap, hoses, thermometer, and flushed everything. N my truck is still overheating some help me please.

Could it be the temperature sending unit is defective? Sounds like you're done everything else.

who did the work? you should ask them- unless it's not a real mechanic just someone who was guessin'- the thermostat is usually responsible for overheating if the system is leak-free-- and maybe all that other stuff was just unnecessary unless you are rebuilding the whole truck- that guessin' gets expensive- have the cooling system pressure tested to make sure there are no leaks- it has to have perfect integrity to work correctly- then, if the system has no leaks, I might try to see if there is still air in the system- if an air bubble gets behind the thermostat, it won't work right- try "burping" (squeezing) the radiator hoses with the engine cold and the radiator cap off- do air bubbles come up?

I have replaced water pump in 94 Ford ranger and leaking coolant from behind. What could it be?