The most reliable Mercedes-Benz engines by the numbers
Mercedes-Benz's most reliable engines come from two golden eras: the pre-2000 over-engineered classics (OM606, M104, M112/M113) and the modern post-2016 generation (OM654, OM656). Both share a design philosophy: simplicity where it matters.
Complete ranking
| Rank | Engine | Score | Verdict |
|---|---|---|---|
| 1 | OM606 | 96/100 | BEST |
| 2 | M112/M113 | 92/100 | BEST |
| 3 | OM648 | 90/100 | BEST |
| 4 | M104 | 85/100 | BEST |
| 5 | OM654 | 85/100 | BEST |
| 6 | OM656 | 82/100 | BUY |
| 7 | OM642 | 82/100 | BUY |
| 8 | M256 | 80/100 | BUY |
| 9 | M264 | 78/100 | BUY |
| 10 | M276 | 78/100 | BUY |
OM606 — 96/100
3.0L NA Diesel I6
Found in: 300D, E 300D
Even the best engines have some issues to watch:
- Glow plug failure (only meaningful issue) — severity minor, typically appears around 80.000 km
- Injection pump seal wear (age-related) — severity minor, typically appears around 200.000 km
Full OM606 reliability report →
M112/M113 — 92/100
V6/V8 NA
Found in: C-Class, CLK, E-Class, G-Class, ML 320, ML 350, S 430, S-Class
Even the best engines have some issues to watch:
- Spark plugs + ignition coils (V6/V8) — severity minor, typically appears around 80.000 km
- Coolant system: thermostat + expansion tank — severity minor, typically appears around 100.000 km
- Air suspension / Airmatic failure (S/ML models) — severity moderate, typically appears around 100.000 km
Full M112/M113 reliability report →
OM648 — 90/100
3.2L CDI Diesel I6
Found in: C-Class, E 320 CDI, E-Class, S-Class
Even the best engines have some issues to watch:
- Glow plugs + injector seals — severity minor, typically appears around 80.000 km
- EGR valve fouling (city use) — severity moderate, typically appears around 80.000 km
Full OM648 reliability report →
M104 — 85/100
M104 2.8/3.2 I6
Even the best engines have some issues to watch:
- Wiring harness biodegradation — severity high, typically appears around 100.000 km
Full M104 reliability report →
OM654 — 85/100
2.0L Diesel I4
Found in: A 180d, A-Class, B-Class, C 220d, C 300d, C-Class, CLA, E 220d
Even the best engines have some issues to watch:
- DPF — better than older MB diesels but still diesel — severity minor, typically appears around 80.000 km
- Minor EGR fouling (best-in-class but not immune) — severity minor, typically appears around 100.000 km
Full OM654 reliability report →
OM656 — 82/100
3.0L Diesel I6
Found in: E 400d, S 350d
Even the best engines have some issues to watch:
- AdBlue / SCR system consumption and faults — severity minor, typically appears around 30.000 km
- DPF + EGR — diesel city driving concern — severity moderate, typically appears around 60.000 km
Full OM656 reliability report →
Generated from EngineScope's reliability database. Reviewed by the editorial team. Methodology →