The Mercedes — Benz OM 651.957 is a 2,143 cc, inline — four turbo — diesel engine produced between 2013 and 2018. It was engineered as a refined, fuel — efficient powerplant for compact and mid — size luxury applications, featuring common — rail direct injection, variable geometry turbocharging (VGT), and double overhead camshafts (DOHC). In standard tune, it delivered 125 kW (170 PS) and 400 Nm of torque, providing responsive performance and strong low — end driveability.…
Production years 2013–2018 meet Euro 5 standards .
The Mercedes-Benz OM 651.957 is a 2,143 cc inline-four turbo-diesel engineered for compact luxury vehicles (2013–2018). It combines common-rail direct injection with a single variable-geometry turbocharger to deliver responsive performance and driving comfort. Designed to meet Euro 5 emissions standards, it balances efficiency with strong low-end torque.
| 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 | 125 kW (170 PS) @ 3,000–4,200 rpm | |
Torque | 400 Nm @ 1,400–2,600 rpm | |
Fuel system | Bosch CRS 2.0 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 GT1544V) | |
Timing system | Double roller chain (front-mounted) | |
Oil type | Refer to vehicle handbook / manufacturer specification | |
Dry weight | 178 kg |
The Mercedes-Benz OM 651.957 was used across Mercedes-Benz's W176/W246/X156 platforms with transverse mounting. This engine received platform-specific adaptations-shortened intake manifolds for compact packaging-and from 2015 the updated emissions calibration for enhanced DPF regeneration, creating minor interchange limits. All adaptations are documented in OEM technical bulletins.
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Field reports and technical service bulletins highlight component wear patterns under high-load operation. Adherence to manufacturer service intervals and approved fluid specifications is critical for long-term reliability.
Analysis derived from manufacturer technical service bulletins and industry workshop records. 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 OM 651.957 offers strong torque and refinement, but early models (2013-2014) showed higher HPFP failure rates under high-mileage use. Later revisions (post-2015) improved pump reliability with updated design and filtration. Well-maintained units with regular oil and fuel filter changes can exceed 250,000 km. Using high-quality diesel and MB 229.51 oil is essential for longevity.
Key issues include high-pressure fuel pump wear, EGR valve/cooling clogging, turbo actuator sticking, and oil leaks from valve cover gaskets. These are documented in Mercedes service bulletins, particularly SIB 22/2013. Fuel quality and maintenance intervals significantly impact reliability, especially in urban or high-load applications.
The OM 651.957 was used in the W176 A-Class (A200 CDI) from 2013–2018, W246 B-Class (B200 CDI) from 2013–2018, and X156 GLA-Class (GLA 200 CDI) from 2015–2018. It was not shared with other Mercedes passenger vehicles but served as a basis for compact derivatives in select markets.
Aftermarket ECU tuning is common on the OM651957 platform, but increasing boost or altering engine parameters accelerates component wear, impacts emissions compliance, and may void vehicle warranties. Any modifications should be evaluated carefully by a qualified specialist.
In an A200 CDI (W176), real-world consumption averages 5.5–6.8 L/100 km (41–51 mpg UK) depending on load and driving style. Highway cruising can achieve ~5.0 L/100 km (57 mpg UK). Heavier SUV use in GLA-Class may exceed 7.3 L/100 km. Economy is competitive for a 2.1L diesel in its class.
Yes. The OM 651.957 is an interference engine. If the timing chain fails or jumps, piston-to-valve contact is likely, resulting in severe internal damage. The front-mounted double roller chain is durable but requires correct tension and lubrication. Any abnormal noise from the timing cover should be investigated immediately.
Mercedes specifies MB 229.51 (5W-30) synthetic oil. This formulation ensures proper turbo bearing and chain lubrication under high load. Oil must be changed every 15,000 km or annually, whichever comes first. Using non-compliant oil can accelerate wear, particularly in the HPFP and turbocharger.
Comprehensive technical documentation and regulatory references
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Regulatory Stability
EU regulations are referenced using CELEX identifiers for long-term stability.
EUR-Lex
EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
GOV.UK: Vehicle Approval & V5C
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)
UK type-approval authority for automotive products.
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.
GOV.UK: Vehicle Approval
UK compliance and certification requirements for imported and modified vehicles.
VCA Certification Portal
Type-approval guidance and documentation.
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