TL* THE CONTACT OWNS AN ONAN INC 4000 WATT OIL/GASOLINE RV GENERATOR (MODEL: 4KWFA26100J, SERIAL NUMBER: 8000060411) THAT WAS BEING USED IN A 2000 ITASCA SPIRIT RV. THE CONTACT STATED THAT THE GENERATOR LEAKED OIL AFTER BEING USED. THE GENERATOR WAS INSPECTED BY A MECHANIC WHO DETERMINED THERE WAS A DEFECT ON THE DESIGN AND THAT THE BLOW OFF VALVE WAS BLOWING OIL INTO THE AIR FILTER. AS A RESULT, OIL WAS ENTERING INTO THE GENERATOR COMPARTMENT AND ACCUMULATING. THE OIL WAS BLOWN TO THE GENERATOR'S MOTOR AND CAUSED THE VEHICLE TO SMOKE. THE GENERATOR WAS NOT REPAIRED. THE APPROXIMATE CURRENT AND FAILURE MILEAGE WAS 120,000.