The Mercedes-Benz OM 612.981 is a 2,996 cc, inline-five, turbocharged diesel engine produced between 2000 and 2005. It features an iron-block, SOHC, 10-valve configuration with indirect injection via prechamber and a Bosch VE mechanical injection pump. Delivering 110 kW (150 PS) and 370 Nm of torque, this engine was engineered for durability and smooth low-end response in executive and light commercial applications.
Fitted to the W210 E-Class and W203 C-Class, the OM 612.981 was designed to provide reliable performance for mixed driving duties. Its driving character emphasizes fuel efficiency and mechanical simplicity, making it well-suited for fleet and high-mileage operation. Emissions compliance was achieved through optimized combustion, EGR, and turbocharging, meeting Euro 3 standards across its production run.
One documented concern is wear in the mechanical injection pump's advance unit, highlighted in Mercedes-Benz Technical Service Bulletin 70.00-P-0004/0. Degradation of internal components can cause incorrect injection timing, leading to hard starting and excessive smoke. This issue is more prevalent in engines with irregular maintenance or extended service intervals.
Production years 2000–2005 meet Euro 3 standards (VCA UK Type Approval #VCA/EMS/5683).
The Mercedes-Benz OM 612.981 is a 2,996 cc inline-five turbocharged diesel engine engineered for executive and light commercial models (2000–2005). It combines indirect injection with a mechanically controlled Bosch VE pump to deliver responsive low-RPM torque and long-term durability. Designed to meet Euro 3 emissions standards, it balances economy and reliability in a mechanically robust package.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,996 cc | |
| Fuel type | Diesel | |
| Configuration | Inline-5, SOHC, 10-valve | |
| Aspiration | Turbocharged | |
| Bore × stroke | 88.0 mm × 98.0 mm | |
| Power output | 110 kW (150 PS) @ 4,200 rpm | |
| Torque | 370 Nm @ 1,800 rpm | |
| Fuel system | Bosch VE mechanical injection pump (indirect injection) | |
| Emissions standard | Euro 3 | |
| Compression ratio | 22.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | KKK K26-2637 turbocharger | |
| Timing system | Gear-driven camshaft and injection pump | |
| Oil type | SAE 10W-40 MB 229.1 | |
| Dry weight | 228 kg |
The turbocharged design provides improved low-RPM torque ideal for mixed urban and highway driving. SAE 10W-40 MB 229.1 oil is essential to maintain lubrication integrity in the high-pressure mechanical injection system and turbocharger bearings. Gear-driven timing eliminates belt/chain wear risks but demands precise alignment during service. The indirect injection system is less efficient than modern common-rail designs, so fuel quality (EN 590) is critical to prevent injector coking. Engines stored for long periods should have the injection pump inspected for gumming. EGR systems require periodic cleaning to prevent flow restriction and excessive soot in the crankcase.
Oil Specs: Requires MB 229.1 specification (Mercedes-Benz SIB 70.00-E-0001/0). Compatible with ACEA B3/B4 standards.
Emissions: Euro 3 certification applies to all 2000–2005 models (VCA Type Approval #VCA/EMS/5683). No market-specific variants.
Power Ratings: Measured under DIN 70020 standards. Output unchanged across model years (Mercedes-Benz Group PT-2000).
Mercedes-Benz Technical Information System (TIS): Docs 612.981-2001, SIB 70.00-P-0004/0, SIB 70.00-E-0001/0
VCA Type Approval Database (VCA/EMS/5683)
DIN 70020 Engine Power Measurement Standard
The Mercedes-Benz OM 612.981 was used across Mercedes-Benz's W210 and W203 platforms with longitudinal mounting. This engine received platform-specific adaptations-fuel tuning variations between saloon and estate applications-and from 2005 was phased out in favour of the OM647 common-rail engine. All adaptations are documented in OEM technical bulletins.
Locate the engine number stamped horizontally on the front-right side of the engine block near the timing cover (Mercedes-Benz TIS 612.981-2001). The 8th VIN digit indicates engine type ('D' for diesel, '6' for 3.0L). Pre-2002 units have a ribbed valve cover; post-2002 revisions use a flat cover. Critical differentiation from OM612.970: OM 612.981 includes a KKK turbocharger and EGR system. Service parts require model-year verification—pump calibration differs between W210 and W203 applications (Mercedes-Benz SIB 70.00-P-0004/0).
The OM 612.981's primary reliability risk is injection pump timing degradation, with elevated incidence in high-mileage or intermittently used vehicles. Internal Mercedes-Benz field reports from 2006 indicated a significant number of OM612.981 units required pump recalibration or replacement before 250,000 km, while VCA records show these engines are among the most durable in long-term fleet use when properly maintained. Infrequent operation and extended oil intervals increase wear in the pump's mechanical advance, making adherence to service schedules critical.
Analysis derived from Mercedes-Benz technical bulletins (2000-2006) and UK DVSA failure statistics (2000-2010). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ OM612981.
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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).
GOV.UK: Vehicle Approval & V5C
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DVLA: Engine Changes & MoT
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Vehicle Certification Agency (VCA)
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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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