The most reliable BMW engines by the numbers
BMW's best engines are among the finest internal combustion engines ever mass-produced. The straight-six is BMW's signature — and the data confirms it. From the M50 to the B58, BMW's inline sixes consistently dominate reliability rankings.
Complete ranking
| Rank | Engine | Score | Verdict |
|---|---|---|---|
| 1 | M50/M52 | 95/100 | BEST |
| 2 | B58 | 93/100 | BEST |
| 3 | M54 | 93/100 | BEST |
| 4 | N52 | 90/100 | BEST |
| 5 | M50 | 88/100 | BEST |
| 6 | M57 | 84/100 | BUY |
| 7 | B48 | 82/100 | BUY |
| 8 | M43 | 82/100 | BUY |
| 9 | B57 | 80/100 | BUY |
| 10 | B47 | 80/100 | BUY |
| 11 | M44 | 78/100 | BUY |
| 12 | N57 | 78/100 | BUY |
M50/M52 — 95/100
2.0-2.8L NA I6
Found in: 3 Series, 320i, 325i, 328i, 5 Series, Z3
Even the best engines have some issues to watch:
- VANOS oil seal wear (M52 only) — severity minor, typically appears around 120.000 km
- Valve cover / oil pan gasket leaks — severity minor, typically appears around 150.000 km
- Cooling system plastics (tank, housing, impeller) — severity moderate, typically appears around 100.000 km
Full M50/M52 reliability report →
B58 — 93/100
3.0L Turbo I6
Found in: 1 Series, 2 Series, 3 Series, 340i, 4 Series, 440i, 5 Series, 540i
Even the best engines have some issues to watch:
- Plastic charge pipe crack — severity minor, typically appears around 60.000 km
- Valve cover gasket oil leak — severity minor, typically appears around 80.000 km
- Coolant expansion tank / line failure — early units — severity moderate, typically appears around 60.000 km
M54 — 93/100
2.2-3.0L NA I6
Found in: 3 Series, 320i, 325i, 330i, 5 Series, X5, Z3, Z4
Even the best engines have some issues to watch:
- Valve cover gasket oil leak — severity minor, typically appears around 100.000 km
- Double VANOS oil seal wear — severity moderate, typically appears around 100.000 km
- Cooling plastics — water pump impeller critical — severity moderate, typically appears around 80.000 km
N52 — 90/100
2.5-3.0L NA I6
Found in: 1 Series, 130i, 3 Series, 325i, 328i, 330i, 5 Series, 520i
Even the best engines have some issues to watch:
- Hydraulic lifter tick on cold start — severity minor, typically appears around 60.000 km
- VANOS solenoid / oil feed failure — severity moderate, typically appears around 80.000 km
- Coolant expansion tank / hose failure — severity moderate, typically appears around 80.000 km
M50 — 88/100
M50 2.0/2.5 NA I6
Even the best engines have some issues to watch:
- Water pump plastic impeller failure — severity high, typically appears around 60.000 km
- VANOS unit wear (M50TU) — severity moderate, typically appears around 100.000 km
M57 — 84/100
3.0L Turbo Diesel I6
Found in: 3 Series, 5 Series, 525d, 530d, 7 Series, X5
No significant reliability issues reported.
Generated from EngineScope's reliability database. Reviewed by the editorial team. Methodology →