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-Class, the OM651.924 was engineered for responsive low-end torque and refined highway performance. Emissions compliance was achieved via exhaust gas recirculation (EGR), a diesel particulate filter (DPF), and urea-based selective catalytic reduction (SCR) in certain markets, enabling full Euro 5 compliance across its production run.
One documented reliability concern is high-pressure fuel pump (CP3.3) wear, particularly under sustained high-load operation. This issue, referenced in Daimler Service Information Bulletin 22/2008, stems from inadequate lubrication and internal wear in the Bosch CP3.3 injection pump. From 2013, revised pump calibration and updated oil specifications (MB 229.51) were introduced to improve longevity.
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 |
The single VGT setup provides strong low-RPM torque ideal for urban driving and towing, but demands strict adherence to 15,000 km oil change intervals using MB 229.51–spec oil to maintain fuel pump and turbocharger longevity. Substandard diesel fuel with poor lubricity can accelerate CP3.3 pump wear, particularly in high-temperature or high-load conditions. Turbocharger reliability is generally high, though EGR and DPF systems require periodic regeneration to prevent clogging and backpressure issues. Pre-2013 models should be inspected for early CP3.3 pumps; post-2013 revisions include improved cam ring hardening. Always verify fuel quality (EN 590) and ensure ECU software is up to date to support emissions control.
Oil Specs: Requires MB 229.51 (5W-30) specification (Mercedes SIB 22/2008). Not compatible with ACEA A/B standards.
Emissions: Euro 5 certification applies to all 2011–2016 models (VCA Type Approval #VCA/EMS/5686).
Power Ratings: Measured under DIN 70020 standards. Output consistent across fuel qualities meeting EN 590 (Daimler TIS Doc. A27500).
Mercedes-Benz Technical Information System (TIS): Docs A26822, A27227, A27062, SIB 22/2008
VCA Type Approval Database (VCA/EMS/5686)
SAE International: DIN 70020 Engine Power Measurement Standard
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.
Locate the engine code stamped horizontally on the front-right cylinder bank near the alternator (Mercedes TIS A26823). The 8th VIN digit indicates engine type ('5' for OM651 series). Pre-2013 models have silver valve covers with black intake manifolds; post-2013 units use black valve covers. Critical differentiation from OM646: OM651.924 uses inline-four layout with single VGT (Garrett GT1749V), while OM646 uses V6 biturbo. Service parts require production date verification—CP3.3 pumps before 08/2012 are incompatible with later units due to internal cam ring redesign (Daimler SIB 22/2008).
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.
Find answers to most commonly asked questions about MERCEDES-BENZ OM651924.
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Regulation (EC) No 715/2007
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