2013 LINCOLN NAVIGATOR Engine Problems

While driving at approximately 65-70 mph on a major interstate, the engine experienced a sudden catastrophic failure without warning. This caused an immediate loss of power and power steering/braking assist, making the vehicle extremely difficult to control in high speed traffic. This sudden stall endangered my life and the lives of nearby motorists. A certified mechanic inspected the engine internals (via borescope) and identified that a valve seat had dropped in the #4 cylinder, causing it to impact and destroy the piston. This 'dropped valve seat' failure is a known defect in Ford/Lincoln 5.4L engines. It occurred despite my meticulous maintenance history and constitutes a latent manufacturing defect that creates an unreasonable safety risk on public highways.