2020 BMW M340I engine problems

Filed Oct 26, 2026 · Engine · OR

Oil pump Issue, oil starvation to engine making it unreliable

Filed Oct 23, 2026 · Engine · TX

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 the cold is when they fail the most, 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 for just the pump, assuming the motor is unharmed. 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 in the car even when no replacement has occurred and the old components are actually in the car. Also, BMW has actively removed the plastic part number out of all dealer networks as well.

Filed Oct 22, 2026 · Engine · TX

I'm reporting a safety issue with BMW vehicles equipped with the B58TU engine, primarily 2019-2021 models. These vehicles have an oil pump with an internal plastic component that regulates oil pressure, and this part is fracturing in the field, causing sudden loss of oil pressure. The failure typically occurs during cold starts in low temperatures. When it fails, oil pressure becomes erratic or is lost entirely, often with little to no warning before engine damage or vehicle disablement. Warning signs, when present, include inability to measure oil level electronically, abnormal oil pressure, or sudden drivetrain malfunction warnings. These can rapidly progress to engine shutdown or severe damage from oil starvation. This creates a dangerous situation because the vehicle can become disabled without warning while driving or after startup. This is especially hazardous when cars become immobilized in traffic or during winter conditions when failures occur most frequently, leaving occupants exposed to freezing temperatures while awaiting assistance. Pump replacement requires extensive disassembly and commonly costs $6,000-$8,000, assuming no engine damage. A critical concern: owners cannot determine if their vehicle has the original plastic pump or the later metal revision. BMW's VIN-based parts lookup now shows updated components even when original plastic parts remain installed, and BMW has removed the original plastic part number from dealer networks entirely. Failures are reported across multiple production years, and the scope of affected vehicles remains unclear. Because this condition causes sudden vehicle disablement without adequate warning, especially in cold weather, I believe this warrants investigation as a potential safety-related defect.

Filed Oct 22, 2026 · Engine · UT

Plastic components in the oil pump went out. BMW has made new oil pumps with metal components that are less fragile and do not fail as often. Outside of warranty these repairs can be very costly. I have had to pay out of pocket for these repairs myself. I do not understand why this is not a recall.

Filed Sep 13, 2026 · Engine · CA

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 the cold is when they fail the most, 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 for just the pump, assuming the motor is unharmed. 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 in the car even when no replacement has occurred and the old components are actually in the car. Also, BMW has actively removed the plastic part number out of all dealer networks as well.

Filed Sep 1, 2026 · Engine · NY

Oil pump for the 2020 model is made with plastic internals. The passage that controls the flow of oil into your engine is made of plastic. The car didn’t even have 40,000 miles and the plastic broke causing the passage to be in a very close to shut position not allowing enough oil to enter the engine in higher rpm. The mechanic told me this is the biggest thing he is starting to see and he works for BMW Service center of Mamaroneck. He’s seen over 150+ B58TU (engine model) of the year 2020 with broken plastic in the oil pump. For the 2021 model year and up to 2026 they have updated the oil pump to metal internals and metal passageways solving the issue but are not helping us 2020 owners and aren’t taking any responsibility blaming it on owners. The repair cost over 3,000 dollars. I understand if it’s something they can’t figure out but they saw it was their own negligence on using better parts and they switch from plastic to metal oil pumps after they saw an increase of over 2,000+ 2020 bmws with the b58tu in it have this issue. There were no warnings, no lights on the dash, no check engine and no codes on the car or when read with a diagnostic scanner. I even included the difference between the 2020 oil pump (plastic) to the 2021 and up oil pump (metal) which was bought from BMW Parts in Mamaroneck. This is an oem part that they updated on their newer cars and won’t take responsibility for their negligence on their 2020 model.

Filed Aug 13, 2026 · Engine · OH

I am reporting a premature oil pump failure on my 2020 BMW M340i xDrive with 42 thousand miles. The vehicle has been well maintained and has not experienced any oil pressure warning lights. However, the electronic engine oil level measurement repeatedly fails to complete once the engine is fully warmed up. I have also received stored BMW fault code 21B2C7 relating to engine oil pressure plausibility/excessive oil pressure. The fault currently shows as inactive, but it was not present previously. I have monitored engine oil pressure using diagnostic software. Pressure is generally around 38–42 psi at hot idle, approximately 44–48 psi during cruising, and can rise into the 60–78 psi range during acceleration. Although these readings are generally stable, the combination of the stored pressure plausibility fault and repeated inability to measure the engine oil level is concerning. I have also noticed a whining/humming noise from the front of the engine at low RPM, particularly during stop-and-go driving and while decelerating in first and second gear. There are numerous owner reports involving premature oil pump failures on BMW vehicles equipped with this generation of the B58 engine. The original oil pump used on earlier vehicles reportedly contains plastic internal components that can deteriorate over time and heat exposure. BMW later revised the oil pump design. BMW Korea has also reportedly begun providing repairs for certain B58 oil pump failures outside the normal warranty period while the issue is being investigated in that market. An engine oil pump is a critical lubrication component and is not a normal maintenance or wear item. Failure of the pump could result in insufficient or excessive oil pressure, loss of lubrication, severe engine damage, engine seizure, or loss of power while driving. I am submitting this complaint so the federal safety agency is aware of the potential pattern of premature oil pump failures affecting 2020 BMW M340i vehicles and

Filed Jul 31, 2026 · Engine · TX

Component Involved:Engine Mechanical / Variable-Displacement Engine Oil Pump (Part #11418635032 / Updated #11419895359) Description of Safety Hazard / Defect:The early-generation B58TU engine features a variable-displacement oil pump equipped with an internal thermoplastic (plastic) adjusting ring. Due to continuous thermal cycling and mechanical stress, this plastic ring is prone to cracking and shattering without warning.When this internal component disintegrates, it causes an immediate loss of oil pressure to critical engine components. This creates a severe safety hazard, as the vehicle can experience a sudden loss of motive power or complete engine seizure while travelling at highway speeds, placing the occupants and surrounding traffic at immediate risk of a collision.Furthermore, a known software bug or sensor interference tied to this specific mechanical failure prevents the iDrive system from successfully completing an electronic oil level measurement, thereby masking the impending failure from the driver until catastrophic engine failure occurs.Relevance of International Actions:In May 2026, BMW Korea officially acknowledged this identical component design flaw by launching a proactive, free preventative repair campaign for B58TU engines manufactured between January 2019 and June 2021. BMW is actively replacing the defective plastic-ring oil pumps with an updated, all-metal version in that market.North American consumers are driving vehicles equipped with the exact same defective part, manufactured during the same window, and facing the same catastrophic safety risks. I am requesting that the agency open a formal defect investigation into BMW North America to mandate a safety recall or an extended component warranty program.

Filed Jul 14, 2026 · Engine · LA

Safety Hazard: Oil Pump Failure Leading to Sudden Engine Stall (BMW B58TU engines) Description of Defect: The oil pump module in the 2020 BMW M340i (G20) and many other models between 2019-2020 contains internal plastic components that are prone to thermal degradation and premature failure. These plastic parts can crack or disintegrate, causing a sudden loss of oil pressure. BMW corrected this in later models with metal parts but failed to issue a recall or the older models containing plastic parts. Safety Risk: A failure of the oil pump leads to insufficient lubrication of critical engine components, which can result in a sudden and complete engine seizure while the vehicle is in motion. This causes an immediate loss of propulsion and power steering assist, significantly increasing the risk of a high-speed collision or being stranded in dangerous traffic conditions. Additional Note: This is a known mechanical defect where a critical engine component (oil pump) relies on non-durable plastic materials, creating an unreasonable safety risk for drivers and passengers due to potential catastrophic engine failure without prior warning.

Filed Jul 6, 2026 · Engine · AZ

I am submitting this complaint regarding a potential safety defect involving the engine lubrication system on my 2020 BMW M340i with the B58 engine. The vehicle was purchased used from a single owner with low mileage and comprehensive maintenance records, with no indication of prior engine or lubrication issues. While traveling at highway speed, the vehicle suddenly displayed a low oil pressure warning and simultaneously entered a protective shutdown strategy, resulting in a significant loss of engine power. This forced me to rapidly slow down and merge across multiple lanes of traffic to reach the shoulder, creating a dangerous situation with a substantial risk of a rear-end or multi-vehicle collision. There were no warning lights, fault messages, drivability concerns, or other symptoms before this incident. According to the authorized BMW dealership that inspected the vehicle, the engine experienced an oil pump failure that caused a loss of oil pressure, resulting in internal engine damage. The dealership found metal shavings in the engine oil and recommended complete engine replacement rather than repairing the oil pump due to the extent of the damage. The vehicle and failed components are available for inspection upon request. Based on the dealership's diagnostic findings, there were no stored oil pressure fault codes prior to the failure; the only oil pressure warning occurred at the time the engine lost power. I am concerned that this indicates the vehicle did not provide meaningful advance warning before a catastrophic failure occurred. I believe this may represent a defect in the oil pump assembly that warrants investigation. I have seen many reports from other owners discussing failures involving the B58 oil pump assembly, including concerns about an internal plastic component that many owners proactively replace with an aftermarket metal component to reduce the risk of failure. This failure posed an incredible safety risk to me and others on the road.