NHTSA complaint #11762587

Owner complaint summary

The BMW B58 Technical Update (B58TU) engine utilizes a variable-displacement oil pump incorporating internal components manufactured from thermoplastic rather than traditional metal. These plastic internal parts are prone to severe thermal degradation and brittleness over time. Under normal operating conditions—and particularly during cold-starts in low ambient temperatures—the plastic elements suffer structural fatigue and catastrophically fracture, destroying the pump's ability to maintain oil pressure. A primary indicator of failure is the vehicle's inability to complete an electronic oil level measurement, quickly followed by a critical "Low Oil Pressure: Stop Engine" warning. This defect poses an immediate and severe hazard to motor vehicle safety. A sudden loss of engine oil pressure while traveling at highway speeds results in immediate oil starvation and catastrophic engine seizure. This causes a sudden loss of motive power and can lead to a loss of power-assisted steering and braking. Operating a vehicle that suddenly stalls or seizes in fast-moving traffic creates an extreme risk of high-speed rear-end collisions and leaves occupants stranded in highly hazardous highway conditions. Because BMW quietly transitioned back to a ruggedized metal oil pump design in later production runs without issuing a safety recall or notice for earlier models, thousands of vehicles remain on the road with an inherently defective, safety-critical engine component. I request that the National Highway Traffic Safety Administration (NHTSA) open a formal safety defect investigation into this component to mandate a safety recall and protect the public.