NHTSA complaint #11720985

Owner complaint summary

I am reporting a safety concern involving BMW vehicles equipped with the B58 Technical Update (B58TU) engine, commonly found in model years 2019–2021. These vehicles utilize a variable-displacement engine oil pump containing an internal thermoplastic adjusting component responsible for regulating oil pressure. Field failures are increasingly being reported in which this internal component fractures, resulting in sudden loss or instability of engine oil pressure. The failure frequently occurs during cold-start operation in low ambient temperatures. When the component fails, oil pressure regulation becomes erratic or is lost entirely. In many cases, drivers receive little or no actionable warning prior to engine damage or vehicle disablement. Reported precursor symptoms include inability to electronically measure engine oil level, abnormal oil pressure behavior, or sudden drivetrain malfunction warnings. Failures may rapidly progress to engine shutdown or severe mechanical damage caused by oil starvation. Loss of lubrication can cause the vehicle to become disabled without warning while driving or shortly after startup. This creates a safety hazard, particularly when vehicles become immobilized in active traffic or during winter conditions where occupants may be exposed to freezing temperatures while awaiting assistance. Replacement of the oil pump requires extensive disassembly of the vehicle and repairs commonly exceed $6,000–$8,000 when engine damage occurs. Owners are currently unable to determine whether their vehicles contain the original thermoplastic oil pump design or a later revised version utilizing metal internal components, as VIN-based parts information now identifies updated components even when no replacement has occurred. Failures have been reported across multiple production years, and affected vehicle population boundaries remain unclear.