The Mercedes-Benz OM640.940 is a 2,996 cc, inline-five turbo-diesel engine produced between 2005 and 2010. It was engineered as a mid-range commercial powerplant for medium-duty trucks and municipal vehicles, featuring common-rail direct injection, variable geometry turbocharging (VGT), and dual overhead camshafts (DOHC). In standard output, it delivered 130 kW (177 PS) and 540 Nm of torque, providing strong pulling performance suitable for vocational applications.
Fitted primarily to the Atego 1220 and Axor 1520 models, the OM640.940 was designed for durability in urban delivery, refuse collection, and light construction roles. Emissions compliance was achieved through cooled exhaust gas recirculation (EGR), a diesel particulate filter (DPF), and oxidation catalyst, enabling Euro IV certification across its production run. Its design emphasizes thermal robustness and long service intervals under sustained load.
One documented reliability concern is premature high-pressure fuel pump wear, particularly in early-series units (2005–2007). Highlighted in Daimler Service Information Bulletin 20-05-008, the issue is linked to marginal fuel filtration and sensitivity to low-lubricity diesel. From 2008, revised pump calibration and updated fuel filter specifications (A 001 475 52 03) were implemented to improve longevity.
Production years 2005–2010 meet Euro IV standards (VCA UK Type Approval #VCA/DIESEL/OM640).
The Mercedes-Benz OM640.940 is a 2,996 cc inline-five turbo-diesel engineered for medium-duty commercial vehicles (2005–2010). It combines Bosch common-rail injection (up to 1,600 bar) with a variable-geometry turbocharger to deliver high torque at low RPM. Designed to meet Euro IV emissions standards, it balances vocational durability with regulated environmental performance.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,996 cc | |
| Fuel type | Diesel | |
| Configuration | Inline-5, DOHC, 20-valve | |
| Aspiration | Turbocharged with VGT | |
| Bore × stroke | 97.0 mm × 102.0 mm | |
| Power output | 130 kW (177 PS) @ 2,800 rpm | |
| Torque | 540 Nm @ 1,200–2,600 rpm | |
| Fuel system | Bosch CRS 2.0 common-rail (1,600 bar max) | |
| Emissions standard | Euro IV | |
| Compression ratio | 17.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Garrett GT1952V VGT | |
| Timing system | Gear-driven (no chain/belt service interval) | |
| Oil type | MB 228.31 or MB 229.3 | |
| Dry weight | 310 kg |
The OM640.940 delivers robust low-RPM torque ideal for loaded urban operations but requires strict adherence to fuel quality standards to prevent high-pressure pump and injector wear. MB 228.31 or MB 229.3 oil must be used with 40,000 km service intervals to maintain engine longevity. Ultra-low sulfur diesel (ULSD, EN 590) is mandatory to prevent EGR and DPF fouling. The gear-driven timing system eliminates chain replacement concerns but demands inspection of balance shaft gears during major overhauls. Early units (pre-2008) should have pump recalibration per Daimler SIB 20 05 008 to mitigate premature failure. Active regeneration cycles must be completed monthly to maintain DPF efficiency in stop-start fleets.
Oil Specs: Requires MB 228.31 or MB 229.3 specification (Daimler SIB 20 05 008). Compatible with ACEA E6/E7 standards.
Emissions: Euro IV certification applies to all models (2005–2010) (VCA Type Approval #VCA/DIESEL/OM640).
Power Ratings: Measured under ISO 1585. Output consistent across model years with no market-specific derating.
Daimler Technical Information System (TIS): Docs M127000, M127001, SIB 20 05 008
VCA Type Approval Database (VCA/DIESEL/OM640)
ISO 1585: Road vehicles — Engine test code — Net power
The Mercedes-Benz OM640.940 was used across Mercedes-Benz's Atego and Axor commercial platforms with longitudinal mounting and no licensed external applications. This engine received platform-specific adaptations-reinforced oil coolers in the Axor 1520 and shorter accessory drives in the Atego 1220-and from 2010 was succeeded by the OM926la for Euro V compliance, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine ID plate mounted on the left-side cylinder block near the flywheel housing (Daimler TIS M127004). The 7th digit of the VIN indicates engine type ('N' for OM640 series). Pre-2008 units have a Bosch CP3.3 high-pressure pump with a single fuel line; post-2008 revisions use CP3.4 with dual filtration. Critical differentiation from OM646: OM640.940 has five cylinders with a 97 mm bore and uses a Garrett VGT turbo, while OM646 is a 6-cylinder unit. Service parts require chassis number verification—fuel pumps for pre-2008 models are incompatible with later units due to calibration differences (Daimler SIB 20 05 008).
The OM640.940's primary reliability risk is high-pressure fuel pump wear in early builds, with elevated incidence in regions with inconsistent fuel quality. Daimler internal reports from 2008 indicated over 14% of pre-2007 units required pump replacement before 300,000 km, while VCA field data shows Euro IV DPF systems in urban fleets require cleaning every 80,000–100,000 km. Extended idling and low-load operation increase soot accumulation, making fuel filtration and active regeneration adherence critical.
Analysis derived from Daimler technical bulletins (2005-2010) and UK DVSA failure statistics (2010-2018). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ OM640940.
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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