The contact owns a 2016 Ford Explorer. The contact stated that while his sister was driving 55-60 MPH, the engine started to overheat, and there was fluid leaking from the vehicle. The contact stated that there was oil in the coolant overflow tank. There were no warning lights illuminated. The vehicle was taken to an independent mechanic who determined that the engine needed to be replaced. The local dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was contacted and referred the contact to the NHTSA Hotline. The failure mileage was approximately 120,000.