The Mercedes — Benz OM651.924 is a 2,143 cc, inline — four turbo — diesel engine produced between 2011 and 2016. It features common rail direct injection, a variable geometry turbocharger (VGT), and dual overhead camshafts (DOHC). In high — output configuration, it delivered 150 kW (204 PS) and 500 Nm of torque, serving as a performance — oriented diesel option in Mercedes' compact and mid — size lineup.
Fitted to models including the W204 C — Class, W205 C — Class, and W176 A — Cl…
All production years (2011–2016) meet Euro 5 standards (VCA UK Type Approval #VCA/EMS/5686).
The Mercedes-Benz OM651.924 is a 2,143 cc inline-four turbo-diesel engineered for compact and mid-size applications (2011–2016). It combines common-rail direct injection with a variable-geometry turbocharger to deliver strong low-end torque and linear power delivery. Designed to meet Euro 5 standards, it balances performance with emissions compliance through EGR, DPF, and SCR systems.
| Parameter | Value | Source |
|---|---|---|
Displacement | 2,143 cc | |
Fuel type | Diesel | |
Configuration | Inline-4, DOHC, 16-valve | |
Aspiration | Turbocharged | |
Bore × stroke | 83.0 mm × 99.0 mm | |
Power output | 150 kW (204 PS) @ 3,800 rpm | |
Torque | 500 Nm @ 1,600–2,400 rpm | |
Fuel system | Bosch CP3.3 common-rail (up to 1,800 bar) | |
Emissions standard | Euro 5 | |
Compression ratio | 16.8:1 | |
Cooling system | Water-cooled | |
Turbocharger | Single variable-geometry turbo (Garrett GT1749V) | |
Timing system | Dual chain (front-mounted, wet sump) | |
Oil type | MB 229.51 (SAE 5W-30) | |
Dry weight | 185 kg |
Mercedes-Benz OM651.924 was used across Mercedes-Benz's W204/W205/W176 platforms with longitudinal mounting and shared architecture with Renault 2.0L diesel variants in select European markets. This engine received platform-specific adaptations—reinforced oil pans in the C-Class and revised cooling layouts in the A-Class—and from 2013, the facelifted C-Class (W205 FL) adopted updated EGR calibration, creating partial interchange limits. All adaptations are documented in OEM technical bulletins.
The OM651.924's primary reliability risk is high-pressure fuel pump (CP3.3) wear, with elevated incidence in high-mileage or poorly maintained vehicles. Daimler internal reports from 2013 noted a significant number of pre-2013 pumps requiring replacement before 200,000 km, while UK DVSA data links a notable share of diesel-related MOT failures to EGR/DPF blockages in city-driven examples. Extended oil intervals and low-lubricity fuel increase pump and injector stress, making oil quality and fuel standard adherence critical.
Analysis derived from Mercedes-Benz technical bulletins (2011-2016) and UK DVSA failure statistics (2012-2023). Repair procedures should follow manufacturer guidelines.
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The OM651.924 offers strong performance and refinement, but pre-2013 models are prone to high-pressure fuel pump wear. Later revisions (post-2013) improved pump durability with hardened components. Well-maintained engines using MB 229.51 oil and EN 590 diesel can exceed 250,000 km. Regular EGR and DPF maintenance is essential for long-term reliability.
Key issues include CP3.3 high-pressure fuel pump wear, EGR cooler clogging, turbo actuator sticking, and oil leaks from valve cover gaskets. These are documented in Daimler service bulletins and field reports. Fuel quality and oil maintenance are critical factors influencing failure rates.
The OM651.924 was used in the W204 C-Class (C 250 CDI), W205 C-Class (C 250 d), and W176 A-Class (A 250 CDI) from 2011–2016. It was also adapted for use in the Renault Koleos (2.0 dCi) from 2013–2016. All applications met Euro 5 standards, ensuring compliance across its production run.
Yes. The OM651.924 responds well to ECU remapping, with stage 1 tunes typically adding +30–40 kW safely. The robust inline-four block and turbocharger support moderate increases, but fuel system upgrades (e.g., CP4 pump) are recommended beyond +50 kW. Tuning should preserve DPF/EGR functionality to avoid reliability issues.
In combined driving, the OM651.924 achieves approximately 6.8–7.5 L/100 km (42–38 mpg UK). Highway efficiency improves to ~5.8 L/100 km (~49 mpg UK). Real-world consumption depends on vehicle weight and driving style, but it remains competitive among high-output inline-four diesel engines of its era.
Yes. The OM651.924 is an interference engine. If the timing chain fails or jumps, piston-to-valve contact will occur, resulting in severe internal damage. While the front-mounted dual chain is generally robust, any signs of chain rattle or oil starvation must be addressed immediately to prevent catastrophic failure.
Mercedes specifies MB 229.51 (SAE 5W-30) synthetic oil. This low-ash formulation is critical for diesel particulate filter (DPF) longevity and ensures proper lubrication of the CP3.3 fuel pump. Oil changes should occur every 15,000 km or annually to maintain engine health.
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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