PARIS, May 18 — Max Verstappen’s luckless pursuit of an endurance racing victory again ended in disappointment yesterday as his Mercedes broke down when leading the 24 Hours of Nuerburgring.

The 28-year-old Dutchman, who is having another difficult season with his Red Bull Formula One team and has threatened to leave the discipline, is competing in a growing number of endurance races in GT3 cars, a category derived from production cars.