BMW B58B30 engine code explained
B58B30 is the full code for BMW's modular 3.0-litre turbo straight-six petrol, the engine in every 340i and M340i, 440i and M440i, M140i and M240i, 540i, 740i, X3 and X4 M40i, X5 and X7 40i, Z4 M40i and the Toyota Supra since 2015. It has been through three generations (B58, B58TU in 2018 to 2019, B58TU2 in 2022) and four output tiers from 320 to 387 bhp. It is widely regarded as the most reliable turbocharged six BMW has built.
Quick answer
The B58B30 is the 3.0-litre straight-six turbo petrol of the BMW B58 family, built 2015-present. Bimmer.AI scores the family 8 / 10: one of the safest used BMW engines to buy. The tables below give every output tier and sticker letter BMW used on this stem and which cars got them; the failure table is the same one that powers the B58 family guide.
How to read B58B30
| Part of the code | Meaning |
|---|---|
| B | B-series modular engine generation (2013 onwards) |
| 58 | engine family number within the B-series |
| B | petrol, longitudinal (rear-drive platform: 1 to 8 Series, X3 to X7, Z4) |
| 30 | displacement in tenths of a litre: 3.0 litres |
| K / U / M / O / T / S + digit | output tier and revision, appended in BMW's internal naming (for example B58B30O1) |
| A / B / C / D | parts-catalogue engine version printed on the engine cover sticker (for example B58B30A) |
B58B30 output tiers and which cars have them
| Code | Output | Cars | Notes |
|---|---|---|---|
| B58B30M0 | 320 to 340 bhp | 340i (F30 / F34 2015-2019), 440i (F32 / F33 / F36 2016-2020), M140i / M240i (F20 / F22 2016-2021, 335 bhp), 540i (G30 2017-2019), X3 M40i (G01 2018-2019, 355 bhp), X4 M40i, Toyota Supra 3.0 (2019) | Original B58 |
| B58B30M1 | 335 to 340 bhp (B58TU) | 540i (G30 2020-2023), X5 xDrive40i (G05 2019-2023), X6 40i, X7 xDrive40i (G07 2019-2022), X5 xDrive45e PHEV engine side, 745e | Technical update: revised cylinder head, injection and cooling |
| B58B30O0 / O1 | 369 to 387 bhp (B58TU high output) | M340i (G20 / G21 2019-2024), M440i (G22 / G23 / G26), X3 M40i and X4 M40i LCI (2020-2024), Z4 M40i (G29 2020 on), M240i (G42 2022 on), 740i (G11 LCI), 840i (G14 / G15 / G16), 640i GT | Upper tier; 48V mild hybrid on most from 2020 |
| B58B30M2 | 375 to 381 bhp (B58TU2), 48V mild hybrid | 740i (G70 2023 on), 540i (G60 2024 on), X5 xDrive40i LCI (G05 2024 on), X6 40i LCI, X7 xDrive40i LCI, M340i LCI (2025 on), X3 M50 (G45 2025 on) | Latest generation with revised turbo and Miller-cycle tuning |
B58B30 sticker letters: B58B30A, B58B30B, B58B30C
The parts letters map cleanly onto the three B58 generations, which is useful: A is the original, B the TU and C the TU2. All three are excellent. Buyer checks are the plastic oil-filter-housing gasket (universal past 80,000 miles), the OEM plastic charge pipe (fit an aluminium one on any tuned car), the electric water pump and thermostat, VANOS solenoids and, on the earliest A cars, intake carbon build-up.
| Sticker code | What it denotes |
|---|---|
| B58B30A | Original B58 (2015 to 2018). |
| B58B30B | B58TU (2018 to 2019 onwards): new head with integrated exhaust manifold changes, revised injection, higher output tiers. |
| B58B30C | B58TU2 (2022 onwards): revised turbo, Miller-cycle valve timing, 48V mild hybrid on most applications. |
Known problems on every B58B30
Failure data is held once, per engine family, so this table is identical to the BMW B58 guide. Cost ranges are indicative UK figures.
| Failure mode | Severity | Frequency | Typical onset | UK repair range |
|---|---|---|---|---|
| Oil filter housing gasket leak | Moderate | Very common | 70 to 130k mi | £220 to £480 |
| Wastegate actuator rattle | Mild | Common | 40 to 100k mi | £200 to £800 |
| Plastic charge pipe failure | Moderate | Uncommon | 60 to 130k mi | £150 to £400 |
| VANOS solenoid weep or failure | Mild | Common | 70 to 140k mi | £180 to £450 |
| Intake valve carbon buildup (pre-2018 direct-injection-only builds) | Moderate | Common | 80 to 130k mi | £350 to £600 |
Long-term verdict
The B58 is one of BMW's strongest modern petrol engines and the natural successor to the N55. Euro 6 ULEZ-compliant from launch, no catastrophic systemic failures documented in the UK used market to date, and a closed-deck block that comfortably handles factory power outputs and aftermarket tuning. The wear items that do appear (oil filter housing gasket, wastegate rattle on early B58s, intake-valve carbon on pre-2018 builds without port injection) are predictable and modest in cost. Post-2018 B58TU variants gain port fuel injection on top of direct injection, which substantially reduces carbon buildup risk. This is a Phase 1 record. Treat the items below as the well-documented wear list, not a complete catalogue.
Check a specific B58B30 listing
Paste any BMW B58 listing, VIN or registration. Bimmer.AI identifies the exact engine and returns the buyer report in 30 seconds.
Run a Bimmer.AI buyer report →Bimmer.AI is designed to help you identify BMW-specific buyer risks before you travel, negotiate, or pay for an inspection. It does not replace a physical inspection by a qualified mechanic, a legal vehicle-history check (e.g. HPI Check), or independent verification of finance, stolen, or write-off status. Repair-cost ranges are indicative UK figures that vary by region, specialist, parts supply, and labour rates.
Frequently asked questions
What is the difference between B58B30M0, M1, O1 and M2?
M0 is the original 2015 B58 at 320 to 340 bhp (340i, 440i, M140i, 540i). M1 is the B58TU from 2018 to 2019 at 335 to 340 bhp (X5 / X7 40i, 540i LCI). O0 and O1 are the high-output TU at 369 to 387 bhp (M340i, M440i, X3 M40i LCI, Z4 M40i, M240i G42). M2 is the B58TU2 from 2022 at 375 to 381 bhp with 48V mild hybrid (740i G70, 540i G60, X5 LCI). Later is better on paper, but every tier has the same excellent reliability record.
B58B30 problems: is there anything to worry about?
Very little that is engine-specific. The known items are the plastic oil-filter-housing gasket (weeps onto the belt past 80,000 miles), the OEM plastic charge pipe (can burst under boost, especially on tuned cars), the electric water pump and thermostat, and VANOS solenoids. None is expensive by BMW standards. The B58 has none of the N54's fuel-system drama or the N55's wastegate rattle.
Which BMWs have the B58B30 engine in the UK?
340i and M340i, 440i and M440i, M140i and M240i, 540i, 640i GT, 740i, 840i, X3 M40i, X4 M40i, X5 xDrive40i and 45e / 50e, X6 40i, X7 40i, Z4 M40i, and the 2 Series Coupe M240i. Plus the Toyota GR Supra 3.0. In every one of them it is the pick of the range for a used buyer who wants performance without the M-car bills.
Which BMWs have the B58B30 engine?
The B58B30 went into the following cars, by output tier. B58B30M0 (320 to 340 bhp): 340i (F30 / F34 2015-2019), 440i (F32 / F33 / F36 2016-2020), M140i / M240i (F20 / F22 2016-2021, 335 bhp), 540i (G30 2017-2019), X3 M40i (G01 2018-2019, 355 bhp), X4 M40i, Toyota Supra 3.0 (2019); B58B30M1 (335 to 340 bhp (B58TU)): 540i (G30 2020-2023), X5 xDrive40i (G05 2019-2023), X6 40i, X7 xDrive40i (G07 2019-2022), X5 xDrive45e PHEV engine side, 745e; B58B30O0 / O1 (369 to 387 bhp (B58TU high output)): M340i (G20 / G21 2019-2024), M440i (G22 / G23 / G26), X3 M40i and X4 M40i LCI (2020-2024), Z4 M40i (G29 2020 on), M240i (G42 2022 on), 740i (G11 LCI), 840i (G14 / G15 / G16), 640i GT; B58B30M2 (375 to 381 bhp (B58TU2), 48V mild hybrid): 740i (G70 2023 on), 540i (G60 2024 on), X5 xDrive40i LCI (G05 2024 on), X6 40i LCI, X7 xDrive40i LCI, M340i LCI (2025 on), X3 M50 (G45 2025 on). The two-letter family badge is B58; any listing that quotes the family code is talking about one of these.
Is the BMW B58B30 reliable?
Bimmer.AI scores the B58 family 8 out of 10, which makes the B58B30 one of the safest used BMW engines to buy. The B58 is one of BMW's strongest modern petrol engines and the natural successor to the N55. Euro 6 ULEZ-compliant from launch, no catastrophic systemic failures documented in the UK used market to date, and a closed-deck block that comfortably handles factory power outputs and aftermarket tuning. The wear items that do appear (oil filter housing gasket, wastegate rattle on early B58s, intake-valve carbon on pre-2018 builds without port injection) are predictable and modest in cost. Post-2018 B58TU variants gain port fuel injection on top of direct injection, which substantially reduces carbon buildup risk. This is a Phase 1 record. Treat the items below as the well-documented wear list, not a complete catalogue.
What does B58B30 mean?
B is the B-series modular engine generation (2013 onwards), 58 is the family number, B means petrol, longitudinal (rear-drive platform: 1 to 8 Series, X3 to X7, Z4), and 30 is the displacement in tenths of a litre (3.0 litres). BMW appends an output tier and revision (K, U, M, O, T or S plus a digit) in its own naming, and the parts catalogue adds a version letter (A, B, C) that is what you see on the engine cover.