Why Does It Fail?
Failure to service the coolant is a primary reason for failure. As coolant becomes more acidic over time, it consumes the aluminum core from the inside out.
Age is a common culprit in the final days of radiators.
Heavy use and being exposed to the elements wear down radiators.
Corrosion, salt and humidity cause a radiator to fail over a period of time.
When corrosion or contamination starts to form, it will slowly decrease the radiators capabilities until it breaks down completely.
Collisions can also cause radiator failure, especially if the underhood becomes tighter due to impact.
What Are the Consequences of Failure?
Car overheats and produces steam/smoke.
Electric fan no longer comes on.
Failed head gasket.
Bad seal between radiator cap and expansion reservoir, or too much air in system after fluid change.