Why is the car not recognizing that its hot?

If your question means there is no warning when the engine overheats, here are some possible reasons:

--temperature sensor in engine and/or cooling system has failed.

--fuse has blown in the circuit that provides power to the temperature sensor, warning gauge or light.

--bulb in warning light is broken.

--temperature gauge is no longer working.

--wiring between some or all of these components is damaged or missing.

Driving without a working temperature gauge or light is risky for your wallet. If the car overheats without giving a warning, by the time the driver notices steam coming from under the hood, the engine may already be permanently damaged or destroyed.