There are three common causes of radiator failure that can result in fluid leaks that lead to critical engine overheating.
Perforations
A stone or other road debris thrown up can
penetrate the radiator causing a leak. Replacement
of the radiator is usually the only reliable,
long-term remedy in this case.
Corrosion
Corrosion in radiators usually occurs as the result
of an incorrect concentration of additive in the
coolant water, or if no additive is present in the
coolant. Corrosion can affect any part of the
radiator, but it most commonly occurs in the areas
where the plastic reservoirs are crimped onto the
aluminium core. In most instances of corrosion, the
damage cannot be repaired reliably, and the radiator
must be replaced.
Excessive vibration
If radiator mounting brackets/rubbers/bushings are
worn, damaged or broken, the radiator can be
subjected to excessive levels of vibration.
Over time the vibrations can cause fluid leaks
between the plastic reservoirs and the aluminium
core. Again, the remedy for this is to replace
the radiator.