Bought a "well-maintained" '05 Outback, registered it, and that day, after driving 40 miles and parking, our daughter started driving it to town and didn't get 2 miles before smoke poured out from under the hood. She pulled off the highway and parked. When I arrived 10 minutes later, there was a dinner-plate size oil puddle under the engine and an oil streak on the road. The seller was speechless when I told him, and I believe he would not have sold this car if he suspected it would burst. He drove it 40 miles to deliver it to me, and he's a Subie guy. I've arranged a tow to a mechanic but I wonder what I might be facing. With no previous indication of trouble, what could have caused this?