Which parts fail
Components named in complaints (engine, cooling system, oil leaks, timing chain, exhaust).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2020 BMW M340I owners, lightly cleaned up (personal details are redacted by NHTSA).
The contact owns a 2020 BMW M340I. The contact stated that the vehicle was repaired under NHTSA Campaign Number: 24V576000 (Electrical System, Engine and Engine Cooling); however, the repair failed to prevent the failure from occurring. The contact stated that shortly after the recall repair was completed, the vehicle hesitated to start. The contact stated that several employees at the local dealer attempted to start the vehicle. The vehicle started; however, several months later, the failure reoccurred. An appointment with the dealer was scheduled to inspect the vehicle. The vehicle was not repaired and needed to be towed. The manufacturer was notified of the failure and referred the contact to the NHTSA Hotline for assistance. The failure mileage was approximately 28,162.
The contact owns a 2020 BMW M340I. The contact stated that while merging onto the highway and accelerating, there was an abnormally loud banging sound coming from the vehicle before the vehicle stalled. The contact was able to coast forward. There were no warning lights illuminated. The contact removed the panels, and there was metal falling out. The contact stated that there was a sizable hole in the engine, and metal was showing from the cam plate and oil pump. The local dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was contacted regarding recalls and warranty coverage but it was recommended that the contact call the NHTSA Hotline for assistance. The approximate failure mileage was 59,015.
The contact owns a 2020 BMW M340I. The contact stated that after an oil change was performed by an independent mechanic, there was a large amount of gray smoke coming from the exhaust pipe while accelerating from a complete stop. There was no warning light illuminated during the failure. The vehicle was taken to various independent mechanics, and the failure was associated with the PCV (Positive Crankcase Ventilation) valve cover. The contact stated that there was a recall on other model vehicles for the failure; however, neither the VIN nor the model vehicle was included in the recall. The manufacturer was notified of the failure. The vehicle was not repaired. The failure mileage was approximately 46,500.
The contact owns a 2020 BMW M340I. The contact stated that upon starting the vehicle, the contact noticed a thick white smoke coming out of the exhaust pipes. In addition, the contact stated that there was an abnormal ticking sound coming from the engine while idling. There was no warning light illuminated. The vehicle had not yet been diagnosed or repaired. The manufacturer had yet to be notified of the failure. The failure mileage was approximately 82,500.
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) 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. Increasing wear on internal engine components and even leading to irreversible engine damage. 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. …
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. …
Hi. I'd like to point out I have not had an incident YET thankfully. However, I want to highlight that the early M340i production releases (2019 and 2020) are HIGHLY likely to experience catastrophic engine failure due to an oil pump being made of plastic on some models. Of the 20 or so complaints listed under this vehicle on NHTSA, I've already seen PLENTY of complaints regarding this issue and people actually experiencing this issue. I believe if a car has a fair chance of causing catastrophic damage to its engine on its own, it poses as a safety risk for anyone in or around the car. The fix is to spend $6000-$7000 to have the oil pump replaced with the new 2021 oil pump, but most normal people cannot afford that easily and are driving around with plastic pumps still hoping for the best. …
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. …
The engine oil pump has failed. The part is available for inspection. The failed oil pump causes the engine to blow up, leaving oil and coolant behind on the road as hazards and causing our vehicle violently spin out on the road. The problem has been reproduced multiple times and claimed by bmw dealerships to be faulty on multiple occasions. Upon further research, it has affected 80% of the 2019 and 2020 g series chassis vehicles with the B58tu engine. BMW has a known problem of failed oil pump. As has my own 2020 bmw m340i. The only warnings we had were the oil not measuring through the interior display, the only way to check it no dip stick, not completing or stopping at 21% with failed measurement. It has first appeared for me at 20k miles, for others as early as 5k miles. The vehicle has not been inspected by police or insurance other than the dealer and local independent shop.
Oil pump manufacturing fault. One of the internal components on the oil pump for these B58 engines contains a ring that is made of plastic. Due to its the nature of this type of material, when it is heated and cooled, over time it becomes brittle and cracks. Damage to this internal component is leading to oil pump failure, and eventually engine failure. There is no recall on this yet, which is highly concerning. Basically my oil pump is a ticking time bomb waiting to fail, and BMW refuses to address the issue. Attached are photos of different oil pumps from the exact same engine as mine, containing the plastic ring which is visibly damaged from repeated exposure to hot and cold temperature fluctuations. Once this ring goes bad, engine damage may be catastrophic.
Related recalls
Engine and engine cooling › Engine › Engine control module (ECU/ECM) › Software
BMW of North America, LLC is recalling certain 2019-2020 X5, X7, 2020 3 Series Sedan, X6, 2020-2021 7 Series Sedan, 2020 8 Series Convertible, 8 Series Coupe, and 2020 8 Series Gran Coupe vehicles. Please see the recall report for the complete list of models.
Remedy: Dealers will update the vehicle software, free of charge. Owner notification letters were mailed September 27, 2024. Owners may contact BMW customer service at 1-800-525-7417.
Engine
BMW of North America, LLC (BMW) is recalling certain 2020 M340i, M340i xDrive, 540i, 540i xDrive, X3 M40i, 2020-2021 X4 M40i, 745Le xDrive, 2019-2021 Z4 M40i, and 2020-2021 Toyota Supra vehicles. During engine start, the engine management software may cause loss of braking assist.
Remedy: Dealers will update the engine management software, free of charge. Owner notification letters were mailed on September 17, 2021. Owners may contact BMW customer service at 1-800-525-7417.
Engine complaints in other M340I years
Frequently asked questions
How common are engine problems on the 2020 BMW M340I?
NHTSA has 42 complaints about the engine & cooling of the 2020 BMW M340I, 79% of the model year's 53 complaints. The component named most often is exhaust system › emission control › crankcase (pcv) (1 mentions).
Is there a recall for 2020 BMW M340I engine problems?
Yes — NHTSA recall 24V-576 (software, Aug 1, 2024); NHTSA recall 21V-598 (engine, Aug 2, 2021). Recall repairs are free at authorized dealers.
At what mileage do 2020 BMW M340I engine problems start?
Half of the complaints with a recorded mileage happened before about 59,000 miles.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.