The Mercedes-Benz OM656.920 is a 2,925 cc, inline-six turbo-diesel engine produced between 2016 and 2020. It features common rail direct injection, variable geometry turbocharging (VGT), and DOHC valvetrain with 24 valves. In standard output form, it delivers 143 kW (195 PS) and 400 Nm of torque, providing strong low-end performance ideal for executive sedan and estate applications.
Fitted to the W213 E-Class (E220d), V213 E-Class Estate (E220d), and C257 CLS (CLS220d), the OM656.920 was engineered for responsive driving dynamics and improved fuel efficiency over its predecessor. Emissions compliance was achieved via cooled exhaust gas recirculation (EGR), diesel particulate filter (DPF), and selective catalytic reduction (SCR) with AdBlue injection, meeting Euro 6 standards across all markets during its production run.
One documented reliability concern is high-pressure fuel pump (HPFP) internal wear, particularly in early production units. This issue, referenced in Mercedes-Benz Service Information Bulletin 20/2016, is attributed to insufficient lubricity in early ultra-low-sulfur diesel formulations. From 2018, revised HPFP internals and updated fuel additive specifications were introduced to improve durability.
All production years 2016–2020 meet Euro 6 standards (VCA UK Type Approval #VCA/EMS/9012). No Euro 6d variant of the OM656.920 was produced.
The Mercedes-Benz OM656.920 is a 2,925 cc inline-six turbo-diesel engineered for executive sedan and coupe platforms (2016–2020). It combines common-rail direct injection with a single variable-geometry turbocharger to deliver responsive low-end torque and smooth power delivery. Designed exclusively to meet Euro 6 standards, it balances efficiency with regulated emissions compliance via SCR/AdBlue technology.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,925 cc | |
| Fuel type | Diesel | |
| Configuration | Inline-6, DOHC, 24-valve | |
| Aspiration | Turbocharged | |
| Bore × stroke | 83.0 mm × 92.0 mm | |
| Power output | 143 kW (195 PS) @ 3,800 rpm | |
| Torque | 400 Nm @ 1,200–3,200 rpm | |
| Fuel system | Bosch CRS 3.0 common-rail (up to 2,200 bar) | |
| Emissions standard | Euro 6 | |
| Compression ratio | 16.5:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Single variable-geometry turbo (Garrett GT1749V) | |
| Timing system | Chain (long-life design, front-mounted) | |
| Oil type | MB 229.52 (SAE 0W-30) | |
| Dry weight | 188 kg |
The OM656.920 provides strong low-end torque ideal for urban and highway driving but requires adherence to 15,000 km oil change intervals using MB 229.52 specification oil to protect the HPFP and turbocharger. Use of EN 590 ultra-low-sulfur diesel is mandatory to prevent injector and pump damage. The Bosch CRS 3.0 system is sensitive to fuel contamination; pre-filter maintenance is advised in regions with variable fuel quality. Early HPFP units (pre-2018) should be inspected per SIB 20/2016; updated pumps with hardened components are recommended for longevity. SCR/AdBlue and DPF systems require periodic regeneration and inspection to maintain emissions compliance and prevent limp-mode events.
Oil Specs: Requires MB 229.52 (0W-30) specification (Mercedes-Benz SIB 20/2016). Not compatible with older 229.51 or ACEA A3/B4 oils.
Emissions: Euro 6 certification applies to all models (2016-2020) (VCA Type Approval #VCA/EMS/9012). No Euro 6d version exists.
Power Ratings: Measured under DIN 70020 standards. Output consistent across fuel grades meeting EN 590 (Mercedes-Benz TIS Doc. A36842).
Mercedes-Benz Technical Information System (TIS): Docs A36158, A36242, SIB 20/2016
VCA Type Approval Database (VCA/EMS/9012)
ISO 1585: Road vehicles — Engine test code — Net power
The Mercedes-Benz OM656.920 was used across Mercedes-Benz's W213/V213/C257 platforms with longitudinal mounting and no licensed external applications. This engine received platform-specific tuning variations-smooth idle control in the W213 and revised transmission mapping in the C257-and from 2018 incorporated HPFP durability updates per service bulletin, creating minor service part distinctions. All adaptations are documented in OEM technical bulletins.
Locate the engine ID plate mounted on the left-side cylinder head near the intake manifold (Mercedes-Benz TIS A36161). The 8th VIN digit indicates engine type ('L' for OM656 series). Pre-2018 models have a Bosch HPFP with black housing and serial prefix 0445 010 003; post-2018 units use a revised pump with silver housing and prefix 0445 010 008. Critical differentiation from OM654: OM656.920 has an inline-six configuration with front-mounted timing covers, while OM654 is an inline-four. Service parts require VIN and production date verification—HPFP kits for pre-2018 engines are not interchangeable with updated designs (Mercedes-Benz SIB 20/2016).
The OM656.920's primary reliability risk is high-pressure fuel pump degradation, with elevated incidence in high-mileage vehicles subjected to extended oil intervals. Internal Mercedes-Benz quality reports from 2018 indicated a notable share of pre-2018 pumps requiring replacement before 200,000 km, while UK DVSA records show diesel-related failures in W213/V213 models often trace to fuel system contamination. Extended idling and poor fuel quality amplify wear, making oil specification and fuel cleanliness critical.
Analysis derived from Mercedes-Benz technical bulletins (2016-2020) and UK DVSA failure statistics (2016-2020). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ OM656920.
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.
