Factory specifications, fluid capacities, torque values, EPA fuel economy and the federal safety record for the 2021 M340i.
The 2021 BMW M340i runs an automatic (S8) transmission, requires 6.8 quarts of 0W-20 engine oil, and carries EPA ratings of 23/32/26 mpg. Within the 2019–2022 complaint window, this model year accumulated 11 owner complaints—far below the 2020 peak of 49 and nearer the 2022 low of 6—with engine-related issues cited as the top complaint area and six recalls issued. That placement situates the 2021 model in a comparatively moderate phase of the run, distanced from the highest complaint volume though still subject to the recall activity and engine-focused feedback that define its reliability record.
Fluid capacities, tune-up values and fuel economy at a glance.
Replacement part sizes and factory part numbers — battery, bulbs, filters and belts.
From the factory this vehicle uses OE oil filter 11428583896. Each part links to every other vehicle that shares it, so a part you already stock may fit more of your fleet than you'd expect.
| Engine oil filter | 11428583896 alt 11428583897 |
| Engine air filter | 13718635102 |
| Spark plug | 12122455258 |
| Battery | 61216806755 alt 61217555719 |
| Front wiper blades | 61619478361 |
| Thermostat | 11539494425 alt 11539494424 |
| Cabin air filter | 64119382885 alt 64119382886 |
Engine, drivetrain, dimensions and economy.
| Transmission | Automatic (S8) |
| Overall length | 185.4 in |
| Overall width | 72 in |
| Overall height | 56.7 in |
| Wheelbase | 112.2 in |
| Curb weight | 3825 lb |
| Track (front / rear) | 62.2 / 63 in |
| Weight distribution (front / rear) | 52/48 |
| EPA city / highway / combined | 23 / 32 / 26 mpg |
| Drivetrain | Rear-Wheel Drive |
| Passenger volume | 94 cu ft |
| Cargo volume | 13 cu ft |
| Recommended fuel | Premium Gasoline |
0–60 mph, quarter-mile, horsepower and torque from independent road tests.
Independent road tests for the M340i of this era, listed by trim and engine — this page spans more than one engine, so no single horsepower figure is shown.
| Year | Trim / engine | 0–60 | ¼ mile | HP | Drivetrain |
|---|---|---|---|---|---|
| 2020 | Sedan 3.0L Turbo I-6 | 3.80 sec | 12.30 sec | 382 hp | RWD |
| 2020 | Sedan 3.0L Turbo I-6 | 3.80 sec | 12.30 sec | 382 hp | RWD |
| 2020 | Sedan 3.0L Turbo I-6 | 4.20 sec | 12.70 sec | 382 hp | RWD |
| 2023 | xDrive Sedan 3.0L Turbo I-6 + Elec | 3.70 sec | 12.20 sec | 382 hp | AWD |
| 2023 | xDrive Sedan 3.0L Turbo I-6 + Elec | 3.80 sec | 12.30 sec | 382 hp | AWD |
| 2025 | Sedan (Shadowline Pack) 3.0L Turbo I-6 + Elec 0.4-kWh | 4.40 sec | 12.80 sec | 386 hp | RWD |
Capacities, torques and tune-up values from the factory service manual.
This engine holds 6.8 qt of 0W-20 engine oil, BMW Hypoid Axle Oil G4 in the differential, DOT 4 brake fluid. Torque lug nuts to 103 ft-lbs. The firing order is 1-5-3-6-2-4.
| Automatic Transmission Fluid | ATF3 |
| Automatic Transmission Fluid Capacity | 9.8 qt |
| Brake Fluid | DOT 4 |
| Clutch Fluid | DOT 4 |
| Differential Gear Oil | BMW Hypoid Axle Oil G4 |
| Differential Gear Oil Capacity | 1.05 qt |
| Engine Oil | 0W-20 |
| Engine Oil Capacity | 6.8 qt |
| Cylinder Head Instructions | Only use new bolts. |
| Oil Pump to Cylinder BLock Bolts/Studs | 168.0 inch lbs. ft-lbs |
| Differential Fill Plug | Final Drive: Use new plug: 44.0 ft-lbs |
| Differential drain Plug | Final Drive: Use new plug ft-lbs |
| Lug Nuts | 103 ft-lbs |
| Cylinder Firing Order | 1-5-3-6-2-4 |
| Refrigerant | R1234yf |
| Oil Group | PAG |
| Oil Type | 46YF |
| Brake Caliper Bolt to Carrier Torque | 26.0 |
| Brake Caliper Carrier to Hub Bolt Torque | Use new bolts. 81.0 ft-lbs |
| ABS Sensor Torque | 6.6 |
| Vented Rotor Minimum Thickness for Replacement | Front: 12.99; Rear: 12.99 |
| 1 | Bolts 1-14 | 22 ft. lbs |
Owner-reported issues, recalls, investigations and service bulletins on record with NHTSA — an unfiltered look at what owners actually experience.
The 2021 BMW M340i occupies a transitional point in its generation’s reliability trajectory, as reflected in the federal data. Complaints spiked sharply in 2020 (49) before dropping to 11 in 2021, suggesting early build issues were largely addressed, though six recalls—down from 10 in 2020 but still elevated—indicate lingering hardware or software concerns. The 2021 model also saw the first investigation of the generation (related to engine stalling, per the data), while TSBs remained high (183), signaling persistent but fixable gremlins rather than systemic failures. Compared to 2022, which showed further improvement with just six complaints and a single recall, the 2021 sits in a middle ground: better than the problematic 2020 launch but not yet as refined as the following year. Engine-related issues dominate the 2021’s complaints (6 of 11), though no fire or crash incidents were reported. **Takeaway:** The 2021 is a reasonable buy if service history confirms recall/TSB work was completed, but a 2022 would offer greater peace of mind.**
All 11 complaints on record, top 6 components.
Source: NHTSA Office of Defects Investigation complaint database.
Showing 2 of 6 campaigns on record for this vehicle.
BMW of North America, LLC (BMW) is recalling certain 2021 2 Series (230i, 230i xDrive, M240i, M240i xDrive), 330e, 330e Xdrive, 4 Series Coupe (430i, 430i xDrive, M440i xDrive) M4 Coupe, M4 Competition Coupe, BMW 4… Remedy: Dealers will inspect the seat belt retractors (including the seat belts) and, if necessary, replace the retractors, free of charge. Owner notification letters were mailed on…
BMW of North America, LLC (BMW) is recalling certain 2021 M340i xDrive, M440i xDrive Coupe, 530i, 530i xDrive, 540i, 540i xDrive, 740Li, 740Li xDrive, 840i Gran Coupe, 840i xDrive Gran Coupe, X5 sDrive40i, X5 xDrive40i… Remedy: BMW will notify owners, and dealers will inspect the connection between the 48-Volt battery and the starter-generator assembly, replacing it if necessary, free of charge. The…
Showing 5 of 183 bulletins on record with NHTSA.
| Bulletin | Date | Component | Summary |
|---|---|---|---|
| B010325 | 2025-04-15 | Structure | The Radiator Grilles Lower Active Air Flap Assembly limited warranty for defects in… |
| B720225 | 2025-04-09 | Electrical System | The Supplemental Restraint Systems (SRS) Front Passenger’s Seat Occupancy Capacitive… |
| B611305 | 2024-01-11 | Electrical System | The electrical system of BMW vehicles has been subject to an ongoing development process… |
| B340714 | 2023-10-13 | Service Brakes, Hydraulic | Functional noises (squealing/honking) when braking shortly before the vehicle comes to a… |
| B240323 | 2023-08-01 | Engine And Engine Cooling | ?A software error may cause an unwanted pressure pulsation in the transmission during a… |
The most common OBD-II codes for this vehicle's emissions system. These are standardized SAE J2012 definitions, not vehicle-specific fault reports.
Decode factory build data for a specific vehicle by VIN.
Find every vehicle that shares this one's battery, bulbs, oil capacity, platform or parts.
Cross-vehicle references for the kinds of data on this page.
6.8 qt of BMW LongLife LL-14FE+ or LL-17FE+ 0W-20, per the factory manual.
NHTSA lists 6 recall campaign(s) for this model year. Check your specific vehicle by VIN.
EPA figures are 23 city / 32 highway / 26 combined mpg.