im thinking of buying one with 80k miles on it. but what do i need checked out or replaced and how much would it possibly cost

 

What year are you considering purchasing? 94-00 Northstar engines are notorious for head gasket issues, mine went at 82,000 on my 96, $3,500 repair. The 01 and up models tend to not have this problem. Look for something that has been maintained, with do***entation, I know this may make it more difficult to locate a car, but its worth it in the long run. Make sure that the previous owner maintained the cooling system and has had the scheduled maintainence done. Also check to see how new the battery is, Deville's require alot of electricity to run all its systems. A battery that is near the end of its life may set of false computer codes and dash lights. Good luck, and leme know what you find.