When your radiator is clogged your cars coolant will not be able to flow freely through the cars radiator and engine so when that happens your engine will overheat.
If you notice your engine temperature is getting too hot then it might be that your radiator has clogged and needs either replaced or flushed out.
The radiator hose at the top should be hot to the touch and have pressure inside it and if not then your radiator could be clogged up.
To see if your radiator is clogged while the engine and cooling system is cooled down remove the radiator cap if you have one and shine a flashlight down it.
Turn the engine on and see if the coolant is flowing through the radiator and if not then your radiator could be clogged.
A radiator shop or just a shop in general should be able to flush the radiator out but sometimes you might need a new radiator.