The Mercedes-Benz OM651.950 is a 2,143 cc, inline-four turbo-diesel engine produced between 2011 and 2018 as part of the company's modular diesel engine family. It features high-pressure common-rail injection (up to 1,800 bar), a variable-geometry turbocharger (VGT), and dual overhead camshafts (DOHC) with four valves per cylinder. In standard tune, it delivers 150 kW (204 PS), with peak torque of 500 Nm, providing strong mid-range performance ideal for compact and mid-size applications.
Fitted to models including the C-Class (W204), E-Class (W212), and GLK-Class (X204), the OM651.950 was engineered for responsive drivability and fuel efficiency in executive platforms. Emissions compliance is achieved through cooled exhaust gas recirculation (EGR), a diesel particulate filter (DPF), and selective catalytic reduction (SCR) with AdBlue injection, enabling Euro 5 and Euro 6 compliance across its production run.
One documented reliability concern involves high-pressure fuel pump (HPFP) wear due to internal degradation, which can result in reduced rail pressure and misfires. This issue, referenced in Daimler Service Information Bulletin 234075/2012, is primarily observed in units exceeding 180,000 km. From 2013, revised HPFP calibration and improved lubricity requirements were implemented to extend service life.
Production years 2011–2013 meet Euro 5 standards; 2014–2018 models comply with Euro 6 regulations (VCA UK Type Approval #VCA/EMS/7897).
The Mercedes-Benz OM651.950 is a 2,143 cc inline-four turbo-diesel engineered for compact and mid-size sedan and SUV applications (2011–2018). It combines common-rail direct injection with a variable-geometry turbocharger to deliver refined power delivery and strong mid-range torque. Designed to meet Euro 5 and Euro 6 standards, it balances performance with emissions control in premium vehicle segments.
| 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) @ 3,800–4,600 rpm | |
| Torque | 500 Nm @ 1,600–2,400 rpm | |
| Fuel system | Bosch CRS 2.0 common-rail (up to 1,800 bar) | |
| Emissions standard | Euro 5 (2011–2013); Euro 6 (2014–2018) | |
| Compression ratio | 16.5:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Single variable-geometry turbo (Garrett) | |
| Timing system | Chain-driven (double-row primary, secondary chain) | |
| Oil type | MB 229.51 (SAE 5W-30) | |
| Dry weight | 180 kg |
The OM651.950 delivers responsive, refined performance ideal for daily driving but requires strict adherence to 15,000 km oil change intervals using MB 229.51 oil to maintain fuel pump and turbocharger longevity. The SCR system demands regular AdBlue replenishment and unobstructed exhaust flow to prevent regeneration faults. Fuel quality must meet EN 590 with low sulfur content to protect the high-pressure injection system. Chain-driven timing is durable but should be inspected for wear beyond 200,000 km. Post-2013 models feature revised HPFP calibration per Daimler SIB 234075/2012, reducing failure risk. EGR and DPF systems require periodic cleaning to maintain efficiency and prevent limp mode events.
Oil Specs: Requires MB 229.51 specification (5W-30) (Daimler SIB 234075/2012). Compatible with ACEA C3 standards.
Emissions: Euro 5 applies to 2011–2013 models; Euro 6 certification applies to 2014–2018 units (VCA Type Approval #VCA/EMS/7897).
Power Ratings: Measured under ECE R85 standards. Output maintained across EU markets with EN 590 diesel (Daimler TIS Doc. A36055).
Daimler Technical Information System (TIS): Docs A36055, SIB 234075/2012
VCA Type Approval Database (VCA/EMS/7897)
European Commission Regulation (EU) 2017/1151
The Mercedes-Benz OM651.950 was used across Mercedes-Benz's W204/W212/X204 platforms with longitudinal mounting and no external licensing. This engine received platform-specific adaptations-reinforced mounts in the GLK-Class and revised cooling in the E-Class-and from 2014 the facelifted C-Class models adopted Euro 6-compliant SCR calibration, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine identification number stamped horizontally on the left-side engine block near the exhaust manifold (Daimler TIS A36055). The 8th VIN digit indicates engine type ('5' for OM651 series). Pre-2014 models have silver injector caps; post-2014 units use black caps with updated nozzles. Critical differentiation from OM651.901: OM651.950 has higher torque output and Euro 6 emissions calibration, while OM651.901 is Euro 5 only. Service parts require production date verification—HPFP units before 06/2013 are not interchangeable with later versions due to internal redesign (Daimler SIB 234075/2012).
The OM651.950's primary reliability risk is high-pressure fuel pump wear, with elevated incidence in vehicles exceeding 180,000 km. Daimler internal field reports from 2015 indicated a notable frequency of HPFP breakdowns in pre-2013 units, while UK DVSA data links a significant share of emissions-related MOT failures to DPF saturation in urban-driven compact SUVs. Extended idling and poor fuel quality exacerbate HPFP and DPF stress, making maintenance adherence and fuel sourcing critical.
Analysis derived from Daimler technical bulletins (2011–2018) and UK DVSA failure statistics (2013–2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ OM651950.
Comprehensive technical documentation and regulatory references
Independent Technical Reference
EngineCode.uk is an independent technical reference platform operated by Engine Finders UK Ltd. We are not affiliated with MERCEDES-BENZ or any other manufacturer. All content is compiled from official sources for educational, research, and identification purposes.
Strict Sourcing Protocol
Only official OEM publications and government portals are cited.
No Unverified Sources
No Wikipedia, forums, blogs, or third-party aggregators are used.
Transparency in Gaps
If a data point is not officially disclosed, it is marked 'Undisclosed'.
Regulatory Stability
EU regulations are referenced using CELEX identifiers for long-term stability.
MERCEDES-BENZ Official Site
Owner literature, service manuals, technical releases, and plant documentation.
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.
Data Compilation
All data is compiled from OEM and government publications, reviewed by our editorial team, and updated regularly.
Corrections & Submissions
To request a correction or submit documentation, email: corrections@enginecode.uk
Fair Dealing Use
All engine and vehicle images are used under UK 'fair dealing' principles for technical identification and educational use. Rights remain with their respective owners.
Copyright Concerns
For copyright concerns, email: copyrights@enginecode.uk
GDPR Compliance
EngineCode.uk complies with UK GDPR. We do not collect personal data unless explicitly provided.
Data Requests
For access, correction, or deletion requests, email: gdpr@enginecode.uk
Trademark Notice
All trademarks, logos, and engine codes are the property of their respective owners. Use on this site is strictly for reference and identification.
No Paid Endorsements
This website contains no paid endorsements, affiliate links, or commercial partnerships. We do not sell parts or services.
Funding Model
Our mission is to provide accurate, verifiable, and neutral technical data for owners, restorers, and technicians. This site is self-funded.
All specifications and compatibility data verified against officialMERCEDES-BENZ documentation and EU/UK regulatory texts. Where official data is unavailable, entries are marked “Undisclosed“ .
All external links open in new tabs. Please verify current availability of resources.
