Engine complaints by model year
Which parts fail
Components named in complaints (engine, cooling system, oil leaks, timing chain, exhaust).
Mileage when the problem started
What owners report
I have been smelling a burning odor in the vehicle for almost a year which the dealership and an independent shop had not been able to diagnose. The car was recently throwing Drivetrain Error codes which prompted a visit to the dealership. They found that the 48v battery and negative cable are burnt and quoted $5680 to replace the battery and cables. After investigating I found that there were recalls for this issue on other BMWs, including the same year and model of my vehicle, but my VIN is not pulling up a recall. The issue is a fire risk and a very expensive repair that should be covered by the manufacturer due to a known defect.
At approximately 20,000 miles, vehicle indicated excessively low oil. The dealer indicated oil level was excessively low but did not identify the problem,. The vehicle was filled and returned to owner. Within 1000 miles, the incident occurred again. Dealer replaced replaced the valve cover claiming that was the issue. Now within +/- 1000 miles, the oil level is again excessively low. I happen to have another identical BMW of the same year and same mileage having exactly the same problem (filing separate complaint).
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.
Related recalls (2)
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.
Frequently asked questions
Which BMW M340I years have engine problems?
By NHTSA complaints, the 2020 (42) and 2021 (7) model years. Engine complaints make up 79% of all complaints for the 2020.
Is there a recall for BMW M340I engine problems?
Yes — 2 recalls, including 24V-576 (software, Aug 1, 2024); 21V-598 (engine, Aug 2, 2021). Recall repairs are free at authorized dealers; check a specific car with the VIN recall check.
At what mileage do BMW M340I engine problems start?
Across all years, half of the complaints with a recorded mileage happened before about 59,000 miles; 50% happened before 50,000 miles.
What part fails most often?
Owners most often name the exhaust system › emission control › crankcase (pcv) (1 mentions).
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.