Radiators usually fail in two ways. Unfortunately, these failures sneak up on us, and may not be obvious until the damage is already done. That’s why maintenance is very important.
Leaks: The most common failure is a leak. Like most parts in a vehicle, the radiator is constructed from aluminum and plastic, to help with fuel economy. It doesn’t take much corrosion or jarring to start a small hole or crack. With all the shielding underneath, and simple evaporation, we might not notice these small leaks until it’s too late, and the car is overheating.
Restriction or Clogging: Restrictions and clogs are caused by the rust and corrosion that develops in the radiator and throughout the coolant system. They’re especially common if there’s been little or no preventive maintenance.
The clogs are brought about by the rust that flakes off and joins the coolant flow. These small rust particles build up in the smaller tubes of the radiator. Clogs and restrictions cause uneven cooling, or the overheating of the engine.