Loud Engine Noise problems of the 2008 Mercedes Benz R350

Tl the contact owns a 2008 mercedes-benz R350. While driving approximately 45 mph, the engine made a loud noise and the vehicle shut off. The vehicle was towed to an independent mechanic who diagnosed that the engine needed to be replaced due to a faulty balance shaft. The engine was replaced, but the failure recurred within a couple of weeks. The vehicle was towed to another mercedes-benz mechanic where the engine was replaced again, but the failure recurred after a couple of days. The vehicle was taken back to an independent mechanic and the engine was replaced a third time. The failure recurred. The manufacturer was made aware of the failures and provided a case number. The dealer was not contacted. The vehicle was not repaired. The failure mileage was 158,000.