The Mercedes-Benz OM642.826 is a 2,987 cc, V6 turbo-diesel engine produced between 2006 and 2013. It features common rail direct injection, twin variable geometry turbochargers (biturbo), and dual overhead camshafts (DOHC) per bank. In standard output, it delivered 140 kW (190 PS) and 440 Nm of torque, serving as a mid-range diesel option in Mercedes' executive sedan and SUV lineup.
Fitted to models including the W211 E-Class, W221 S-Class, and W164 ML-Class, the OM642.826 was engineered for responsive low-end torque and smooth power delivery. Emissions compliance was achieved via exhaust gas recirculation (EGR), a diesel particulate filter (DPF), and urea-based selective catalytic reduction (SCR) in certain markets, enabling Euro 4 compliance across production with select 2010+ models meeting Euro 5 standards.
One documented reliability concern is high-pressure fuel pump (CP3.3) wear, particularly under sustained high-load operation. This issue, referenced in Daimler Service Information Bulletin 22/2008, stems from inadequate lubrication and internal wear in the Bosch CP3.3 injection pump. From 2009, revised pump calibration and updated oil specifications (MB 229.51) were introduced to improve longevity.
Production years 2006–2009 meet Euro 4 standards; 2010–2013 models may have Euro 5 compliance depending on market (VCA UK Type Approval #VCA/EMS/5679).
The Mercedes-Benz OM642.826 is a 2,987 cc V6 twin-turbo diesel engineered for executive and luxury SUV applications (2006–2013). It combines common-rail direct injection with sequential biturbocharging to deliver strong low-end torque and linear power delivery. Designed to meet Euro 4 (and select Euro 5) standards, it balances performance with emissions compliance through EGR, DPF, and SCR systems.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,987 cc | |
| Fuel type | Diesel | |
| Configuration | V6, DOHC, 24-valve | |
| Aspiration | Twin-turbocharged (biturbo, sequential VGT) | |
| Bore × stroke | 88.0 mm × 82.1 mm | |
| Power output | 140 kW (190 PS) @ 3,600 rpm | |
| Torque | 440 Nm @ 1,600–2,400 rpm | |
| Fuel system | Bosch CP3.3 common-rail (up to 1,800 bar) | |
| Emissions standard | Euro 4; later models Euro 5 (market-dependent) | |
| Compression ratio | 16.8:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Twin variable-geometry turbo (Garrett GT1549V & GT1749V, sequential) | |
| Timing system | Dual chain (front-mounted, wet sump) | |
| Oil type | MB 229.51 (SAE 5W-30) | |
| Dry weight | 218 kg |
The sequential biturbo setup provides strong low-RPM torque ideal for urban driving and towing, but demands strict adherence to 15,000 km oil change intervals using MB 229.51–spec oil to maintain fuel pump and turbocharger longevity. Substandard diesel fuel with poor lubricity can accelerate CP3.3 pump wear, particularly in high-temperature or high-load conditions. Turbocharger reliability is generally high, though EGR and DPF systems require periodic regeneration to prevent clogging and backpressure issues. Pre-2009 models should be inspected for early CP3.3 pumps; post-2009 revisions include improved cam ring hardening. Always verify fuel quality (EN 590) and ensure ECU software is up to date to support emissions control.
Oil Specs: Requires MB 229.51 (5W-30) specification (Mercedes SIB 22/2008). Not compatible with ACEA A/B standards.
Emissions: Euro 4 certification applies to all 2006–2009 models (VCA Type Approval #VCA/EMS/5679). Euro 5 compliance applies to select 2010–2013 export models.
Power Ratings: Measured under DIN 70020 standards. Output consistent across fuel qualities meeting EN 590 (Daimler TIS Doc. A27500).
Mercedes-Benz Technical Information System (TIS): Docs A26810, A27220, A27055, SIB 22/2008
VCA Type Approval Database (VCA/EMS/5679)
SAE International: DIN 70020 Engine Power Measurement Standard
The Mercedes-Benz OM642.826 was used across Mercedes-Benz's W211/W221/W164 platforms with longitudinal mounting and shared architecture with Chrysler 3.0L diesel variants in North American markets. This engine received platform-specific adaptations—reinforced oil pans in the ML-Class and revised cooling layouts in the S-Class—and from 2009, the facelifted E-Class (W211 FL) adopted updated EGR calibration, creating partial interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the front-right cylinder bank near the alternator (Mercedes TIS A26815). The 8th VIN digit indicates engine type ('6' for OM642 series). Pre-2008 models have silver valve covers with black intake manifolds; post-2008 units use black valve covers. Critical differentiation from OM629: OM642.826 uses twin VGT turbos (Garrett GT1549V + GT1749V), while OM629 uses a single VGT. Service parts require production date verification—CP3.3 pumps before 08/2008 are incompatible with later units due to internal cam ring redesign (Daimler SIB 22/2008).
The OM642.826's primary reliability risk is high-pressure fuel pump (CP3.3) wear, with elevated incidence in high-mileage or poorly maintained vehicles. Daimler internal reports from 2009 noted a significant number of pre-2009 pumps requiring replacement before 200,000 km, while UK DVSA data links a notable share of diesel-related MOT failures to EGR/DPF blockages in city-driven examples. Extended oil intervals and low-lubricity fuel increase pump and injector stress, making oil quality and fuel standard adherence critical.
Analysis derived from Mercedes-Benz technical bulletins (2006-2012) and UK DVSA failure statistics (2012-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ OM642826.
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Regulation (EC) No 715/2007
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