My cayenne's coolant pipes broke at 84k miles. The symptom of this is when all your radiator fluid starts pouring out into the street. It seems like all pre-05 cayenne's have this issue eventually. It's causes by defective plastic coolant pipes. The fix is to have Porsche "upgrade" them to metal pipes for $3,000. There is currently a class action lawsuit pending for this.
2004 Porsche Cayenne S Problem Reports
Newest 2004 Porsche Cayenne S Problem Reports
A no start or stalling condition may develop do to a failing fuel pump. A faulty fuel pump will require replacement. Our technicians recommend to inspect internal fuel tank connections for leaks whenever replacing the fuel pump.
Tire wear can be problematic, very dependent on driving style. Our technicians recommend regular tire inspection and replacement when necessary.