What these engines share
The current-generation 2.0-litre premium diesels: Mercedes OM654 (2016–present, aluminium block, 1950cc) vs BMW B47 (2014–present, modular architecture). Both use SCR/AdBlue systems and represent the state of the art in diesel passenger car engines.
OM654 vs B47 at a glance
| OM654 | B47 | |
|---|---|---|
| Brand | Mercedes-Benz | BMW |
| Score | 85/100 | 80/100 |
| Verdict | BEST | BUY |
| Type | 2.0L Diesel I4 | 2.0L Turbo Diesel I4 |
| Known issues | 2 | 3 |
OM654 — 85/100 (BEST)
Found in: A 180d, A-Class, B-Class, C 220d, C 300d, C-Class, CLA, E 220d
Key issues
- DPF — better than older MB diesels but still diesel — severity minor, cost €1.000, onset 80.000 km
- Minor EGR fouling (best-in-class but not immune) — severity minor, cost €500, onset 100.000 km
B47 — 80/100 (BUY)
Found in: 1 Series, 2 Series, 2 Series Active Tourer, 218d, 3 Series, 320d, 320d GT, 4 Series
Key issues
- DPF blockage — city driving — severity high, cost €1.500, onset 50.000 km
- EGR valve / cooler carbon fouling — severity moderate, cost €800, onset 80.000 km
- Timing chain tensioner (front-mounted) — severity moderate, cost €1.200, onset 100.000 km
Verdict: OM654 wins by 5 points
The OM654 scores 85/100 vs the B47's 80/100 — a 5-point difference. A close call — both engines are in similar territory. Check the specific issues that matter to you.
Which one should you buy?
Both are excellent modern diesels. The OM654 is the first aluminium-block diesel from Mercedes and represents a clean-sheet design. The B47 has a longer production history and more real-world data. Neither is a bad choice — pick by the car.
Generated from EngineScope's reliability database. Reviewed by the editorial team. Methodology →