First things first, you should make sure that you never open the radiator cap when the engine is hot. Hot coolant and steam can come out and seriously scald you. Always wait for the engine to cool down before you open the radiator cap. This is perhaps the most basic thing we can tell you but it is very important for your safety to understand this.

The most common issues with radiators involve dirt or loose debris clogging within the radiator. These things can block up the fluid flow through the radiator which results in overheating. If your car is overheating despite normal coolant levels, pop the hood to see if the radiator is blocked. If there isn’t anything clearly visible, there’s a chance of an internal clogging.

In this case, open the radiator cap after the car cools down and check the fluid and radiator for brown discoloration or any dirt floating within the coolant. If that is indeed the problem, you need to drain the coolant and replace it.

Leaks are also a pretty common failure in radiators. Even the smallest hole or crack in the aluminum body of the radiator can cause leakage that will lead to overheating.