Sounds like you need a new water pump or you could have air in the cooling system
I have a promblem with that too, my car would overheat very fast, it was a faulty NEW thermostat. It still runs hot, I think I need a new water pump
Remove the Radiator and have it serviced if they are able to. If not you will need to replace it, would be a good time to replace the Radiator hose's as well. Hope This Helps.
I would be thinking it is a head gasket.
If it is leaking coolant. And you changed the thermostat. I would then move to this section. Flush the radiator and the heater core. This can be done at a certified shop with a reliable mechanic.
Stuck thermostat, clogged radiator.
if your radiator is in good condition with no leaks from hoses then i would recommend removing the thermostat out then place the thermostat housing back on top up coolant a check your flow by removing cap from radiator. If flow is good then it sounds like a blown head gasket.
This question is not complete. . Need to know if you've replaced radiator, thermostat, hoses etc. Are you asking this question *after* yo checked the thermostat, changed, added or drained the system?
Heater core (radiator) needs to be cleaned or changed
have you changed the thermostat. If you have flused the rad. and it still gets hot I would say more than likely it is the therm. Make sure the outside of the rad. or fins are washed out to. good luck.
If the radiator or reservoir cap is bad it could cause overheating because the system will not build up the proper pressure. Also the fan clutch could be worn out which would keep the fan from spinning fast enough to cool the radiator.
In most cases if your follow the upper radiator hose from the radiator to the engine, the thermostat would be located inside the "gooseneck" at the engine end of the upper hose.
Follow the top radiator hose from the radiator to the engine . The engine cooling thermostat would be in a housing that is bolted to the front of the intake manifold