Key here is
Porsche identified a manufacturing quality issue with the supplier?s application of adhesive to coolant pipe fittings that resulted in elevated failure rates in approximately 6,800 early production 997 generation vehicles (MY 2007 and early MY 2008). ODI?s analysis of field data showed that the age-adjusted failure rate for these vehicles was approximately six times greater than MY 2001 through 2005 996 generation vehicles and MY 2008 through 2011 997 generation vehicles built after a process improvement for adhesive application was implemented by the supplier.