The Mercedes Benz OM651.912 is a 2,143 cc, inline — four turbo — diesel engine produced between 2008 and 2016. It features common rail direct injection, variable geometry turbocharging (VGT), and dual overhead camshafts (DOHC), delivering refined performance and strong low — end torque across compact and mid — size platforms. In standard tune, it produces 100 kW (136 PS) with peak torque of 320 Nm, optimized for urban efficiency and light — duty applications.
Fitted to mod…
Production years 2008–2011 meet Euro 5 standards; 2012–2016 models comply with Euro 6 depending on market (VCA UK Type Approval #VCA/EMS/5677).
The Mercedes Benz OM651.912 is a 2,143 cc inline-four turbo-diesel engineered for compact and mid-size applications (2008–2016). It combines common-rail direct injection with a variable-geometry turbocharger to deliver responsive low-end torque and motorway refinement. Designed to meet Euro 5 and Euro 6 standards, it balances long-term durability with regulated emissions performance.
| Parameter | Value | Source |
|---|---|---|
Displacement | 2,143 cc | |
Fuel type | Diesel | |
Configuration | Inline-4, DOHC, 16-valve | |
Aspiration | Turbocharged (VGT) | |
Bore × stroke | 83.0 mm × 99.0 mm | |
Power output | 100 kW (136 PS) @ 3,000–4,200 rpm | |
Torque | 320 Nm @ 1,400–2,600 rpm | |
Fuel system | Bosch CRS 2.0 common-rail (up to 2,000 bar) | |
Emissions standard | Euro 5 (pre-2012); Euro 6 (post-2012) | |
Compression ratio | 15.5:1 | |
Cooling system | Water-cooled | |
Turbocharger | Single variable-geometry turbo (Garrett GT1549V) | |
Timing system | Double-row roller chain (front-mounted) | |
Oil type | MB 229.51 (SAE 5W-30) | |
Dry weight | 185 kg |
The Mercedes Benz OM651.912 was used across Mercedes Benz's W204/W246/W639 platforms with longitudinal mounting and adapted for transverse applications in front-wheel-drive variants. This engine received platform-specific adaptations-shorter intake manifolds in the B-Class and reinforced mounts in the Vito-and from 2012 the facelifted C-Class adopted the Euro 6-compliant OM651DE22LA with revised EGR and SCR calibration, creating interchange limits. All adaptations are documented in OEM technical bulletins.
The OM651.912's primary reliability risk is high-pressure fuel pump wear on early builds, with elevated incidence in mixed urban/highway use. Internal Daimler quality reports from 2013 noted a significant number of pre-2012 units requiring HPFP replacement before 150,000 km, while UK DVSA records associate SCR-related faults with AdBlue system neglect in city-driven vehicles. Extended service intervals and poor fuel quality increase pump and injector stress, making fluid quality and schedule adherence critical.
Analysis derived from Daimler technical bulletins (2010–2016) and UK DVSA failure statistics (2014–2022). Repair procedures should follow manufacturer guidelines.
The most common questions about engine codes, what they mean, how to find them and how this database works
The OM651.912 is generally durable with strong low-end torque and good fuel economy, but early models (2008–2011) are prone to HPFP wear. Later revisions (post-2012) improved pump reliability and emissions control. Regular servicing with MB 229.51 oil and adherence to maintenance intervals greatly enhance longevity, especially for SCR and DPF systems.
Key issues include high-pressure fuel pump failure (especially pre-2012), AdBlue/SCR system faults, EGR and intake carbon buildup, and occasional timing chain tensioner wear. These are documented in Daimler service bulletins and verified through UK DVSA failure data, particularly in urban-driven vehicles with short trips.
This 2.2L diesel was used in the C-Class (W204), B-Class (W246), and Vito (W639) from 2008–2016. It appears in C200 CDI, B200 CDI, and V200 CDI trims. Mitsubishi also used a licensed version in the Delica D:5 (2.2L DI-D) from 2010–2019. Most applications are Euro 5; post-2012 units meet Euro 6 standards.
Yes. The OM651.912 responds well to ECU remapping, with stage 1 tunes typically adding +20–35 kW safely. The robust inline-4 architecture and VGT support increased output, but upgrades should include enhanced cooling and fuel system monitoring. Over-tuning without supporting mods risks HPFP and turbo longevity.
Excellent. In a C200 CDI (W204) from 2010, combined consumption is ~5.3 L/100 km (~53 mpg UK). Highway runs can achieve ~4.7 L/100 km (~60 mpg UK). Real-world figures vary by driving style, but 50–56 mpg UK is typical for a well-maintained OM651.912 on mixed routes.
Yes. The OM651 series is an interference engine. If the timing chain fails or skips, pistons can contact open valves, resulting in catastrophic internal damage. Regular inspection of the chain and tensioner—especially in high-mileage units—is essential to prevent costly repairs.
Mercedes specifies SAE 5W-30 oil meeting MB 229.51 standard. This low-ash formulation is critical for DPF and SCR system longevity. Oil changes should occur every 15,000 km or annually to maintain engine and emissions system health, particularly for urban-driven vehicles.
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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DVLA: Engine Changes & MoT
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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
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