Check the fan thermostat.
Have you replaced the heating core yet?
Water Pump or Thermostat. May have to change water pump to replace thermostat.
Could be defective thermostat, bad fan clutch, insufficient fan shroud, plugged or inadequate radiator, or underperforming water pump.
Thermostat, low coolant, inoperative radiator fan, failed water pump, plugged radiator, head gasket.
Either the thermostat was not the problem, or you put it in backwards.
Low coolant, inoperative water pump, head gasket failure, inoperative radiator fan, etc.
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
If you're confident that the pump and thermostat are still OK, I'd check for collapsed hoses, or a bad fan or temperature sensor which tells the fan to turn on. FriPilot
fuse, wiring.... how long do u let it run before turning it off??..I would look to the fan relay next. also the electric fan thermostat if the car has one
Thermostat not opening/ closing properly. You need to buy a new thermostat rated for your engine. The thermostat is located under a housing usually near the water pump on your engine. Remove the 2 bolts, lift out the thermostat,, take the car for a drive without it in place, check for overheating.. If it doesn't overheat again replace your old thermostat with a new one. In Australia we usually leave them out all together. Just remember to check and change your coolant regularly. Hope this helps.
just because the thermostat is new doesnt make it good your supposed to boil it in water to see if it opens and closes so it may be bad. if your car is low on oil it will overheat also or start the car and watch the radiator hose it it collapses then the hose is clogged and the water isn't flowing right which will cause it to overheat.