sounds like your thermostat is stuck closed, maybe some of the debris loosened from the flush is blocking it.
Could be the thermostat not opening
Have flushed complete cooling system replaced water pump radiator thermostat clutch fan added 2gal straight anti freeze then filled to capacity with water and truck is still over heating. What else could possibly be wrong
The thermostat is off because it may have reached the desired temperature or there could be an issue with the heating or cooling system.
have you flushed your radiator or changed the thermostat it could be stuck
water pump
Could be your electric fan on the radiator is shot, or the relay is bad.
If your thermostat is not allowing the temperature to rise, it could indicate a problem, but it's not necessarily bad. It might be due to issues like incorrect settings, a malfunctioning sensor, or a problem with the heating system itself. Before concluding that the thermostat is faulty, check the settings and ensure the heating system is functioning properly. If issues persist, it may be time to consider replacing the thermostat or seeking professional help.
There could be many reasons. Not enough coolant or bad flow, faulty thermostat, low oil. If the coolant freezes then it will overheat. If your car continues to overheat then you should have the coolant flushed and thermostat replaced.
it could either be your thermostat is bad, the radiator is bad, or you could have a blown head gasket.
it could be the thermostat needs to be changed or the heater core needs to be flushed out.these would be the cheaper things to try first.
could be a bad thermostat try replacing it answer try flushing out your heater core also
It could be a clogged radiator or cracked head or bad head gasket.