I bought a late model BMW from Sam. As soon as I got it off the lot my troubles began. While spending over $1500 to repair a cooling problem (that Sam would not address) I discovered that an additive had been used to prevent the engine from smoking. Without the additive, the car began smoking like a chimney. On further investigation, we found that the compression was low in all six cylinders. When I called Sam about this problem, he suggested I buy a used engine to replace the one he sold me. You decide. Should I be expected to dump thousands of dollars into this car? Or, should Sam buy back the piece of junk he dumped on me?