The Mercedes-Benz OM629.911 is a 3,022 cc, V6 turbo-diesel engine produced between 2005 and 2013. It forms part of the BlueTEC emissions-reduction initiative, featuring common-rail direct injection, variable geometry turbocharging (VGT), and dual overhead camshafts (DOHC). In standard applications it delivers 150 kW (204 PS) and up to 540 Nm of torque, primarily for executive and off-road platforms.
Fitted to key models including the W211 E-Class, W221 S-Class, and W164 ML-Class, the OM629.911 was engineered for smooth long-distance cruising and towing capability. Emissions compliance was achieved through exhaust gas recirculation (EGR), diesel particulate filter (DPF), and selective catalytic reduction (SCR) in later models, enabling Euro 4 compliance initially and Euro 5 from 2008 onward.
One documented reliability concern is high-pressure fuel pump (HPFP) degradation under sustained high-load operation, noted in Mercedes-Benz Service Bulletin 22/2010. This failure mode is linked to fuel quality sensitivity and inadequate filtration in early production runs. From 2009, revised HPFP calibration and improved fuel system monitoring were implemented across the OM62x series to mitigate premature wear.
Production years 2005–2007 meet Euro 4 standards; 2008–2013 models comply with Euro 5 (VCA UK Type Approval #VCA/EMS/5678).
The Mercedes-Benz OM629.911 is a 3,022 cc V6 turbo-diesel engineered for luxury and SUV platforms (2005–2013). It combines common-rail direct injection with a variable geometry turbocharger and SCR-based aftertreatment to deliver refined performance and reduced NOx emissions. Designed to meet Euro 5 standards from 2008, it balances towing capability with improved fuel economy.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 3,022 cc | |
| Fuel type | Diesel | |
| Configuration | V6, DOHC, 24-valve | |
| Aspiration | Turbocharged with VGT | |
| Bore × stroke | 88.0 mm × 82.1 mm | |
| Power output | 150–165 kW (204–224 PS) | |
| Torque | 510–540 Nm @ 1,600–2,400 rpm | |
| Fuel system | Bosch CRS 3.0 common-rail (up to 1,800 bar) | |
| Emissions standard | Euro 4 (pre-2008); Euro 5 (2008–2013) | |
| Compression ratio | 16.8:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Single variable-geometry turbo (Garrett GT1749V) | |
| Timing system | Dual roller chains (longitudinal layout) | |
| Oil type | MB 229.51 (SAE 5W-30) | |
| Dry weight | 198 kg |
The V6 layout provides smooth, linear power delivery ideal for highway cruising and towing, but requires strict adherence to 15,000 km oil service intervals using MB 229.51 specification oil to protect the high-pressure fuel system and turbocharger. The Bosch CRS 3.0 fuel pump is sensitive to fuel quality; ultra-low-sulfur diesel (EN 590) is mandatory to prevent injector and pump wear. SCR-equipped variants require AdBlue refills every 10,000–15,000 km to maintain emissions compliance. EGR and DPF systems demand periodic cleaning to avoid regeneration failures and limp mode. Post-2009 models benefit from updated HPFP firmware and improved ECU diagnostics per SIB 22/2010.
Oil Specs: Requires MB 229.51 (5W-30) specification (Mercedes-Benz SIB 20 1012). Compatible with ACEA C3 and low-SAPS requirements.
Emissions: Euro 5 certification applies to 2008–2013 models only (VCA Type Approval #VCA/EMS/5678). Pre-2008 units meet Euro 4.
Power Ratings: Measured under ISO 1585 standards. 165 kW output requires EU5 diesel fuel and functional SCR system (Mercedes-Benz TIS Doc. A36510).
Mercedes-Benz Technical Information System (TIS): Docs A35720, A36105, SIB 22 2010
VCA Type Approval Database (VCA/EMS/5678)
ISO International Standards: ISO 1585 Road Vehicles - Engine Test Code
The Mercedes-Benz OM629.911 was used across Mercedes-Benz's W211/W221/W164 platforms with longitudinal mounting and shared design principles with Chrysler’s 3.0L CRD engines in North American markets. This engine received platform-specific adaptations—reinforced engine mounts in the W164 and revised cooling routing in the W221—and from 2009, the facelifted W211 BlueTEC models adopted SCR-based aftertreatment, creating interchange limits. Partnerships allowed Chrysler’s 3.0L CRD to leverage the OM629 architecture. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front right cylinder bank near the alternator (Mercedes-Benz TIS A35750). The 8th VIN digit indicates engine type ('A' for OM629 series). Pre-2008 models lack SCR hardware; post-2008 BlueTEC variants have AdBlue tank and injector. Critical differentiation from OM642: OM629.911 has single VGT turbo and no twin-turbo setup. Service parts require production date verification—HPFP units before 06/2009 are incompatible with later models due to calibration changes (Mercedes-Benz SIB 22 2010).
The OM629.911's primary reliability risk is high-pressure fuel pump (HPFP) failure on early builds, with elevated incidence in mixed urban/highway use. Internal Daimler quality reports from 2011 indicated over 15% of pre-2009 units required HPFP replacement before 150,000 km, while UK DVSA records show SCR-related faults account for a significant share of emissions failures in BlueTEC models. Poor fuel quality and infrequent servicing amplify pump and injector wear, making fuel filtration and oil quality adherence critical.
Analysis derived from Mercedes-Benz technical bulletins (2008–2013) and UK DVSA failure statistics (2013–2022). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ OM629911.
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