TL* THE CONTACT OWNS A 2012 KIA OPTIMA HYBRID. WHILE DRIVING APPROXIMATELY 45 MPH, THE VEHICLE MADE A THUMPING NOISE AND A LOUD BOOM SOUND WAS HEARD FROM THE REAR OF THE VEHICLE. THE CONTACT NOTICED BROWN SMOKE COMING FROM THE REAR OF THE VEHICLE. EVENTUALLY, THE SMOKE TURNED BLACK AND APPEARED FROM THE FRONT AND REAR OF THE VEHICLE. THE CONTACT ALSO NOTICED OIL LEAKING FROM UNDERNEATH THE VEHICLE. THE VEHICLE WAS TOWED TO THE DEALER, MARK KIA, WHERE IT WAS DIAGNOSED THAT SLUDGE WAS IN THE ENGINE AND THE ENGINE NEEDED TO BE REPLACED. THE VEHICLE WAS NOT REPAIRED. THE MANUFACTURER PROVIDED CASE NUMBER: 12369116. THE VIN WAS UNKNOWN. THE APPROXIMATE FAILURE MILEAGE WAS 76,000.