I have a friend who once had a very clean 97 Jetta 2.0. Nice car, very clean, ran great. VW uses an oil / coolant heat exchanger to cool the oil, and there is a rubber seal in there that fails after 10 years or so. It will start weeping then generally let go, dumping out all the oil. This happened to his car has he was driving down the highway. He saw the flashing oil light and heard the loud no oil pressure alarm, but because he didn't smell anything or feel a loss of power he kept on driving... until the motor quit.
He then had it towed to a shop who told him that the motor was done, and that the 2.0 motors were hard to come by. I think he sold the car to the shop for $100. He tells me this a month after the deal went down and I inform him I know of 4 2.0 motors for about $200 each in local junkyards.
Oh well... Now he drives a Cobalt.
-J