In 1999 Dumbreck escaped uninjured from a violent crash during the 1999 24 Hours of Le Mans race when his No. 5 Mercedes-Benz CLR somersaulted into the woods at about . An aerodynamic design flaw caused the front of the car to rise and then flip without any external contact; Mark Webber had already suffered similar crashes in the No. 4 car during the Thursday night practice and the Saturday morning Warm-up. The remaining No. 6 car was retired immediately, and the team withdrew from all other planned entries in endurance racing and the American Le Mans Series.