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 models including the W204 C-Class, W246 B-Class, and Vito (W639), the OM651.912 was engineered for fuel economy and durability in mixed-use environments. Emissions compliance was achieved via exhaust gas recirculation (EGR), diesel particulate filter (DPF), and selective catalytic reduction (SCR) with AdBlue injection, enabling Euro 5 compliance across most markets and Euro 6 in post-2012 variants.
One documented reliability concern is high-pressure fuel pump (HPFP) wear, particularly in early-build units, highlighted in Daimler Service Bulletin 22 0511. Premature wear is linked to fuel quality and extended service intervals. From 2012, revised pump internals and updated calibration improved longevity, aligning with the transition to Euro 6 emissions standards.
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 OM651.912 delivers strong low-RPM torque ideal for city driving and light commercial use but requires strict adherence to 15,000 km oil change intervals using MB 229.51–compliant oil to ensure chain and turbo longevity. The Bosch CRS 2.0 fuel system demands ultra-low-sulfur diesel (EN 590) to prevent HPFP wear. SCR-based emissions control requires periodic AdBlue refills and regeneration cycles; neglect can lead to limp mode. Early models (pre-2012) should be inspected for HPFP wear per Daimler SIB 22 0511. EGR and DPF systems benefit from regular highway runs to prevent clogging.
Oil Specs: Requires MB 229.51 specification (Daimler SIB 22 0511). Supersedes ACEA B4 and C3 standards.
Emissions: Euro 5 certification applies to pre-2012 models only (VCA Type Approval #VCA/EMS/5677). Euro 6 compliance applies to 2012–2016 units depending on market.
Power Ratings: Measured under DIN 70020. Output maintained across temperature ranges with ECU adaptive tuning (Daimler TIS Doc. A32175).
Daimler Technical Information System (TIS): Docs A32175, A32176, SIB 22 0511
VCA Type Approval Database (VCA/EMS/5677)
SAE International: J1349 Engine Power Certification Standards
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.
Locate the engine code stamped horizontally on the front face of the cylinder block near the timing cover (Daimler TIS A32175). The 8th VIN digit indicates engine type ('6' for OM651 series). Pre-2012 models feature silver valve covers with green gaskets; post-2012 Euro 6 units have black valve covers with blue gaskets. Critical differentiation from OM651.916: OM651.912 has a smaller VGT turbo (Garrett GT1549V) and lower power output. Service parts require production date verification—HPFP units before 06/2011 are incompatible with later revisions due to internal pump redesign (Daimler SIB 22 0511).
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.
Find answers to most commonly asked questions about MERCEDES-BENZ OM651912.
Comprehensive technical documentation and regulatory references
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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