Some of the signs that tell you that your car is overheating are as follows
The temperature or light gauge warning light comes on indicating that the engine is overheating
There is a burning smell coming from the engine, which is most likely the singing or burning of oil, or it could be due to the burning of plastic or rubber components in the engine.
The engine may start to produce ticking noises. This is because the oil is no longer able to lubricate the moving parts of the engine, therefore clearances in the engine will start to tick.
Coolant may escape from the reservoir and may leak onto the ground.
Steam may be seen rising from the coolant reservoir or the radiator cap.
Engine power will be severely reduced as a result of an overheating engine. Pistons will not be able to move smoothly within the cylinders and may cause loss of power.