My wife was driving east in Northern Indiana after leaving Chicago on I-65, when the car started knocking, so she pulled off on US 30, and made it halfway up the ramp when smoke was everywhere. Fire department came, said they thought it was a busted hose, and had it towed to nearest dealership in Naperville, where they said there was a hole in the block, $14,000 to fix. I had it towed home and found a dealer to fix it at $11,000. It was 6 months after time warranty, Mercedes Benz strung me along for 6 weeks evaluation my service records and waiting for 2nd opinion, then said they would not help me at all! I am done with Mercedes Benz, they are not the people they used to be. I would advise anyone I know, and I have already, do not buy a Mercedes Benz. I have a gear head friend who state that the blocks on these turbocharged 4 cylinders are not cast blocks, but that would not affect what I suspect was a wrist pin failure. My service records were in accordance with required maintenance.