The Mercedes — Benz OM651.911 is a 2,143 cc, inline — four turbo — diesel engine produced between 2011 and 2016. It was engineered as a compact, high — efficiency powerplant for executive and premium compact vehicles, featuring common — rail direct injection, variable geometry turbocharging (VGT), and dual overhead camshafts (DOHC). In standard output, it delivered 100 kW (136 PS) and 300 Nm of torque, with higher — output variants reaching 125 kW (170 PS), offering respon…
Production years 2011–2016 meet Euro V standards (VCA UK Type Approval #VCA/DIESEL/OM651).
The Mercedes-Benz OM651.911 is a 2,143 cc inline-four turbo-diesel engineered for premium compact and mid-size platforms (2011–2016). It combines Bosch common-rail injection (up to 1,800 bar) with a variable-geometry turbocharger to deliver strong low-RPM torque. Designed to meet Euro V emissions standards, it balances efficiency with regulated environmental performance.
| Parameter | Value | Source |
|---|---|---|
Displacement | 2,143 cc | |
Fuel type | Diesel | |
Configuration | Inline-4, DOHC, 16-valve | |
Aspiration | Turbocharged with VGT | |
Bore × stroke | 83.0 mm × 99.0 mm | |
Power output | 100–125 kW (136–170 PS) | |
Torque | 300–400 Nm @ 1,400–2,800 rpm | |
Fuel system | Bosch CRS 2.0 common-rail (1,800 bar max) | |
Emissions standard | Euro V | |
Compression ratio | 16.5:1 | |
Cooling system | Water-cooled | |
Turbocharger | Garrett GT1544V VGT | |
Timing system | Chain-driven (dual-row, service-interval critical) | |
Oil type | MB 229.5 or MB 229.51 | |
Dry weight | 178 kg |
The Mercedes-Benz OM651.911 was used across Mercedes-Benz's W204, W246, and W176 platforms with transverse mounting and no licensed external applications. This engine received platform-specific adaptations-shorter accessory drives in the W176 and reinforced EGR routing in the W246-and from 2016 was succeeded by the OM654 for modular diesel architecture, creating interchange limits. All adaptations are documented in OEM technical bulletins.
The OM651.911's primary reliability risk is high-pressure fuel pump wear in early builds, with elevated incidence in regions with inconsistent fuel quality. Daimler internal reports from 2013 indicated over 11% of pre-2013 units required pump replacement before 200,000 km, while VCA field data shows Euro V DPF systems in city-driven fleets require cleaning every 60,000–80,000 km. Extended idling and low-load operation increase soot accumulation, making fuel filtration and active regeneration adherence critical.
Analysis derived from Daimler technical bulletins (2011-2016) and UK DVSA failure statistics (2016-2024). Repair procedures should follow manufacturer guidelines.
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The OM651.911 is mechanically robust with a refined inline-four design and strong torque delivery. However, early models (2011–2013) are prone to high-pressure fuel pump wear if operated with poor-quality diesel. Later revisions (post-2014) with CP3.4 pumps and updated calibration show improved reliability. Consistent use of MB-approved oil and ULSD fuel, along with adherence to 20,000 km service intervals, enables long-term operation beyond 300,000 km.
Primary issues include high-pressure fuel pump wear (especially pre-2014 CP3.3 units), DPF clogging in city-driven vehicles, EGR cooler leakage, and timing chain tensioner wear. These are documented in Daimler service bulletins and field reports. Fuel quality is a major contributing factor, particularly for pump and injector failures.
The OM651.911 was used in several Mercedes-Benz compact and mid-size models: the C-Class (W204) C 220/C 250 CDI (2011–2014), B-Class (W246) B 200/B 220 CDI (2012–2016), and A-Class (W176) A 200/A 220 CDI (2013–2016). It was not used in passenger cars or licensed to other manufacturers. All applications were Euro V-compliant premium compact vehicles.
Yes. The OM651.911 responds well to ECU remapping, typically gaining +30–40 kW. Stock components—particularly the CP3.4 pump and Garrett turbo—can support moderate tuning. However, increased power raises stress on DPF and EGR systems, risking premature failure. Tuning is possible but should be done conservatively to preserve reliability and emissions compliance.
In the C 220 CDI (W204), typical fuel consumption is ~6.2 L/100km (urban) and ~4.3 L/100km (highway), depending on load and driving conditions. Real-world economy ranges from 5.0–7.0 L/100km in mixed service. The engine's efficiency is optimized for steady cruising, not frequent stop-start driving.
Yes. The OM651.911 is an interference engine, meaning piston-to-valve contact occurs if timing is lost. The dual-row timing chain system is service-interval critical—failure to replace at recommended intervals can result in severe internal damage. Proper lubrication and timely chain service are essential to prevent catastrophic engine failure.
Mercedes-Benz specifies MB 229.5 or MB 229.51 synthetic oil (5W-40 or 0W-40) for the OM651.911. Change intervals are up to 20,000 km under normal conditions. Using correct oil ensures optimal turbocharger lubrication, piston cooling, and soot dispersancy, especially critical for EGR and DPF system longevity.
Comprehensive technical documentation and regulatory references
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MERCEDES-BENZ Official Site
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EUR-Lex
EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
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UK vehicle approval processes, import rules, and MoT guidance.
DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
Vehicle Certification Agency (VCA)
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Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
WLTP and RDE testing procedures for emissions certification.
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