I just fixed my broken 2005 cavalier with 65000 miles today. it all began when i smelled fuel . turns out my fuel rail and fuel pressure regualtor were both leaking . luckily junk yard had 2004 complete head . 50 dollars later it is fixed. estimated dealer parts including o rings which i did not purchase (300 dollars) My question is why the hell were they leaking????????????????????????????????????????????????????????????

because it has 65000 miles on it.....not uncommon

O'rings shouldn't have cost that much. Head replacement seems like major overkill for leaky o'rings. And yea, sometimes those o'rongs aren't perfectly seated during factory assembly, and just eventually start to leak.