could be alot of things, either check debris in the coils of radiator or check the thermostat. Make sure shraud is undamaged or you can flush the motor and radiator, a radiator flush can be done yourself or at any quick stop lube shop
Is it at the end of the top radiator hose at the engine?
It is under the alternator on the back of the engine. Just follow the belt down from the back of the alternator.
Try changing the pcv valve. Also check for blockage on the tube going to it.
The engine is overheating.
Air inside engine
generally if an engine overheats, but then does not overheat when heater is turned on, is a good indication that the engine thermostat is stuck and needs replacing
What causes a 1998 Pontiac transport to run hot and engine shuts off
with a scan tool you can take the cables off of your battery for 10 minutes and then replace them and that will reset it also
A bad water pump or thermostat can cause an engine to overheat. A plugged (clogged) radiator or heater core may also cause an engine to overheat.
The lack of air intake designed to flow into the motor.
The engine will overheat and the pistons will seize.
Engine thermostat is where your upper radiator hose hooks to the top of the engine