The following are a few very important common failures that are not related to manufacturer defect and therefore not covered under warranty. 

What you need to know about Complete Radiators in general...particularly Aluminum Radiators....

Improper Flush 
Radiators require a thorough flush of the radiator, engine block, overflow tank and heater core. Failure to do so leads to the mixing of coolants and contaminants creating a deadly coolant cocktail.

Electrolysis 
Electrolysis is the systematic removal of the protective layer on the inside of the radiator tubes due to improper vehicle grounding. Electrical grounding problems can stem from poor installation of aftermarket accessories or uncorrected vehicle collision damages.

Corrosion 
Believe it or not, anything short of a 50/50 mix of good coolant and distilled water is a recipe for accelerated internal corrosion. We call it the coolant cocktail effect. Tap water, dirty water, spring water, recycled antifreeze or water with high trace elements of minerals will create problems for aluminum radiators not normally recognized in copper cores. We can’t emphasize enough the need to educate installers on the unique properties of aluminum radiators. Failure to do so only creates an undue increase in the number of warranty claims that are the responsibility of the installer and not the distributor or manufacturer. Proper flush at installation, a 50/50 mix of distilled water and a new vehicle approved coolant, along with the right education make for long-lasting aluminum radiators and fewer warranty claims.