What these engines share
The N55 (2010–2017) and B58 (2015–present) represent the generational shift in BMW's straight-six turbo architecture. The B58 replaced the N55 across the entire range — from the 340i to the Supra. Both are 3.0-litre single-turbo sixes, but the B58's closed-deck block and revised cooling make it a fundamentally more durable engine.
N55 vs B58 at a glance
| N55 | B58 | |
|---|---|---|
| Brand | BMW | BMW |
| Score | 79/100 | 89/100 |
| Verdict | BUY | BEST |
| Type | 3.0L Turbo I6 | 3.0L Turbo I6 |
| Known issues | 9 | 7 |
N55 — 79/100 (BUY)
Found in: 1 Series, 2 Series, 3 Series, 335i, 335i GT, 435i, 5 Series, 535i
Key issues
- Coolant pipe / banjo bolt seals — severity minor, cost €250, onset 80.000 km
- Plastic charge pipe crack — severity minor, cost €300, onset 80.000 km
- Turbo wastegate rattle — severity minor, cost N/A, onset 97.000 km
- Electric water pump failure — severity moderate, cost €700, onset 48.000 km
B58 — 89/100 (BEST)
Found in: 1 Series, 2 Series, 3 Series, 340i, 4 Series, 440i, 5 Series, 540i
Key issues
- Oil pump plastic ring cracks — oil pressure loss (2018-2022 engines) — severity high, cost €5.500, onset 48.000 km
- Crankshaft guide bearing wear — early manual F30 340i (service action) — severity minor, cost N/A, onset N/A
- Oil filter shears off in its housing — severity minor, cost N/A, onset N/A
- Plastic charge pipe crack — severity minor, cost €200, onset 60.000 km
Verdict: B58 wins by 10 points
The B58 scores 89/100 vs the N55's 79/100 — a 10-point difference. A meaningful difference — the B58 has fewer issues and lower repair risk.
Which one should you buy?
The B58 is the better engine in every measurable dimension. Buy the N55 only if budget forces the decision — the F30 340i with B58 commands a premium over the F30 335i with N55, and that premium is justified.
Generated from EngineScope's reliability database. Reviewed by the editorial team. Methodology →