The Mercedes-Benz OM646.983 is a 2,685 cc, inline-five turbo-diesel engine produced between 2010 and 2015 as part of the company's compact 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 510 Nm, providing strong mid-range performance ideal for executive and compact SUV applications.
Fitted to models including the C-Class (W204), E-Class (W212), and GLK-Class (X204), the OM646.983 was engineered for responsive drivability and fuel efficiency in mid-size 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 compliance across its production run.
One documented reliability concern involves high-pressure fuel pump (HPFP) wear, which can result in reduced injection pressure and misfires. This issue, referenced in Daimler Service Information Bulletin 234076/2010, is primarily observed in units exceeding 200,000 km. From 2012, revised HPFP calibration and improved lubricity requirements were implemented to extend service life.
All production years 2010–2015 meet Euro 5 emissions standards (VCA UK Type Approval #VCA/EMS/7895).
The Mercedes-Benz OM646.983 is a 2,685 cc inline-five turbo-diesel engineered for mid-size sedan and SUV applications (2010–2015). 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 standards, it balances performance with emissions control in premium vehicle segments.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,685 cc | |
| Fuel type | Diesel | |
| Configuration | Inline-5, DOHC, 20-valve | |
| Aspiration | Turbocharged | |
| Bore × stroke | 83.0 mm × 99.0 mm | |
| Power output | 150 kW (204 PS) @ 3,600–4,600 rpm | |
| Torque | 510 Nm @ 1,600–2,400 rpm | |
| Fuel system | Bosch CRS 2.0 common-rail (up to 1,800 bar) | |
| Emissions standard | Euro 5 | |
| Compression ratio | 17.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Single variable-geometry turbo (Garrett) | |
| Timing system | Chain-driven (double-row primary, secondary chain) | |
| Oil type | MB 229.5 (SAE 5W-30) | |
| Dry weight | 202 kg |
The OM646.983 delivers responsive, refined performance ideal for daily driving but requires strict adherence to 15,000 km oil change intervals using MB 229.5 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-2012 models feature revised HPFP calibration per Daimler SIB 234076/2010, reducing failure risk. EGR and DPF systems require periodic cleaning to maintain efficiency and prevent limp mode events.
Oil Specs: Requires MB 229.5 specification (5W-30) (Daimler SIB 234076/2010). Compatible with ACEA B5/B6 standards.
Emissions: Euro 5 certification applies to all 2010–2015 models (VCA Type Approval #VCA/EMS/7895).
Power Ratings: Measured under ECE R85 standards. Output maintained across EU markets with EN 590 diesel (Daimler TIS Doc. A37055).
Daimler Technical Information System (TIS): Docs A37055, SIB 234076/2010
VCA Type Approval Database (VCA/EMS/7895)
European Commission Regulation (EC) No 715/2007
The Mercedes-Benz OM646.983 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 2012 the facelifted C-Class models adopted updated 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 A37055). The 8th VIN digit indicates engine type ('F' for OM646 series). Pre-2012 models have silver injector caps; post-2012 units use black caps with updated nozzles. Critical differentiation from OM648.910: OM646.983 has an inline-five layout and single VGT turbo, while OM648.910 uses a V6 configuration. Service parts require production date verification—HPFP units before 06/2012 are not interchangeable with later versions due to internal redesign (Daimler SIB 234076/2010).
The OM646.983's primary reliability risk is high-pressure fuel pump wear, with elevated incidence in vehicles exceeding 200,000 km. Daimler internal field reports from 2014 indicated a notable frequency of HPFP breakdowns in pre-2012 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 (2010–2015) and UK DVSA failure statistics (2012–2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ OM646983.
Comprehensive technical documentation and regulatory references
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MERCEDES-BENZ Official Site
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EUR-Lex
EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
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