I have done a lot of looking at these cars...particularly the Seville STS. Recently I have become aware of the oil leak problem that some Northstars have. I have done some searching to research this, but I still have questions. Is this a design flaw in all of the engines, just certain years, or does it just randomly pop up in higher mileage engines? I was really almost set on making one of these my new car this coming summer, but now I am not so sure. If I bought one, and 3 months later it starts leaking oil, I would get a litle heated if I had to tear the entire car apart to drop the bottom half of the engine. I am just basically wondering how big of a problem this is and if it is limited to certain years. Thanks for your time.