OM656
Mercedes-Benz · 3.0L Diesel I6
2017–present
"Flagship modern MB diesel. Inline-6 smoothness returns. MHEV. GLE/GLS/S-Class. Excellent highway. Early data strong."
Mileage Risk Timeline
When problems typically appear — enter your mileage to see your risk zone
Known Issues 2
DPF + EGR — diesel city driving concern
▸DPF warning, EGR codes, limp mode
Modern diesel: better than older MB units but city-only use still causes DPF/EGR fouling.
OM656 in E-Class GLE: mixed use drivers fine. Athens city-only: consider petrol M256 instead.
AdBlue / SCR system consumption and faults
▸AdBlue warning, SCR faults, NOx system alerts
Modern Euro 6 diesel with full SCR/AdBlue system. AdBlue needs topping every 10-15k km.
AdBlue widely available at Greek stations. System fault diagnosis needs Mercedes specialist.
Models with OM656 3
Related Guides
Other Mercedes-Benz Engines
Tuning Potential
300hp Stage 1
Frequently Asked Questions
Is the Mercedes-Benz OM656 reliable?
The Mercedes-Benz OM656 scores 82/100 with a verdict of BUY. It has 2 documented issues with total repair costs between €500 and €2,000.
What are the common problems with the OM656?
The most common issues are:
- DPF + EGR — diesel city driving concern — moderate, repair cost €400–€1,200, 60,000 km–120,000 km
- AdBlue / SCR system consumption and faults — minor, repair cost €100–€800, 30,000 km–∞
What cars use the Mercedes-Benz OM656?
How much does it cost to repair the OM656?
Total potential repair costs for all 2 known issues range from €500 to €2,000. The most expensive issue is typically .
What years was the OM656 produced?
The Mercedes-Benz OM656 was produced from 2017 to present. It is a 2999cc I6 diesel engine.
Scores are calculated from documented issues, repair costs, and failure patterns across thousands of owner reports and technical sources. Learn about our methodology. Always inspect before you buy.