The contact owns a 2019 BMW M850I. The contact stated that upon starting the vehicle, there was an abnormal coolant odor inside the cabin of the vehicle. There was no warning light illuminated. The vehicle was taken to a local dealer to be diagnosed, and the contact was informed that the expansion tank was faulty and needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure. The approximate failure mileage was 60,128.