The Mercedes-Benz M272.921 is a 3,498 cc, V6 petrol engine produced between 2005 and 2011. It features a DOHC 24-valve configuration with variable valve timing (VVT) on both intake and exhaust camshafts, delivering 180 kW (245 PS) and 310 Nm of torque. This engine utilizes multi-point fuel injection and electronic throttle control, providing balanced performance and refinement in executive and luxury segments.
Fitted to models such as the W211 E-Class, W203 C-Class, and W204 C-Class, the M272.921 was engineered for smooth acceleration and quiet cruising comfort. Emissions compliance was achieved through dual three-way catalytic converters and oxygen sensor feedback, allowing Euro 4 compliance for pre-2009 units and Euro 5 on later builds depending on market specification.
One documented concern is premature wear of the intake camshaft adjusters, which can lead to timing misalignment and reduced performance. This issue, referenced in Mercedes-Benz Service Bulletin 02.2010.02, is linked to internal oil passage clogging under extended service intervals. From 2009, revised camshaft adjusters with improved oil filtration were implemented across the M272 series to enhance reliability.
Production years 2005–2008 meet Euro 4 standards; 2009–2011 models may have Euro 5 compliance depending on market (VCA UK Type Approval #VCA/EMS/5680).
The Mercedes-Benz M272.921 is a 3,498 cc V6 petrol engine engineered for mid-size and executive platforms (2005–2011). It combines multi-point fuel injection with dual variable valve timing to deliver linear power delivery and strong mid-range torque. Designed to meet Euro 4 (and market-specific Euro 5) standards, it balances refinement with regulated emissions control.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 3,498 cc | |
| Fuel type | Petrol | |
| Configuration | V6, DOHC, 24-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 88.0 mm × 85.0 mm | |
| Power output | 180 kW (245 PS) @ 6,000 rpm | |
| Torque | 310 Nm @ 2,500–5,000 rpm | |
| Fuel system | Multi-point fuel injection (ME 2.8 ECU) | |
| Emissions standard | Euro 4 (pre-2009); Euro 5 (2009–2011, market-dependent) | |
| Compression ratio | 10.7:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Chain-driven (dual-row, non-interference) | |
| Oil type | MB 229.5 (SAE 5W-40) | |
| Dry weight | 182 kg |
The naturally aspirated V6 design provides smooth, linear power delivery ideal for highway cruising but requires strict adherence to 15,000 km oil change intervals to prevent camshaft adjuster clogging. MB 229.5 (5W-40) oil is essential due to its high-shear stability and anti-wear additives protecting the dual VVT system. Extended idling or frequent short trips can accelerate carbon buildup in the intake tract. The ME 2.8 ECU is sensitive to low battery voltage, which may cause driveability issues. Post-2009 models feature upgraded cam adjusters; pre-2009 units should use high-quality oil and monitor for rough idle or timing faults. Dual catalytic converters require regular full-load operation to prevent thermal degradation.
Oil Specs: Requires MB 229.5 (5W-40) specification (Mercedes-Benz SIB 02.2010.02). Supersedes ACEA A3/B4 requirements.
Emissions: Euro 4 certification applies to pre-2009 models only (VCA Type Approval #VCA/EMS/5680). Some 2009-2011 models meet Euro 5 depending on market.
Power Ratings: Measured under DIN 70020 standards. Output remains consistent across fuel grades (Mercedes-Benz TIS Doc. A027204).
Mercedes-Benz Technical Information System (TIS): Docs A027200, A027201, A027202, SIB 02.2010.02
VCA Type Approval Database (VCA/EMS/5680)
DIN Standards: DIN 70020 Engine Power Measurement
The Mercedes-Benz M272.921 was used across Mercedes-Benz's W203/W211 platforms with longitudinal mounting and adapted for transverse applications in the W204 C-Class. This engine received platform-specific adaptations-shorter intake manifolds in the W204 and revised engine mounts in the W211-and from 2009 the updated W211 facelift adopted revised camshaft adjusters and oil specifications, creating service part interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped vertically on the right side of the cylinder block near the exhaust manifold (Mercedes-Benz TIS A027206). The 8th VIN digit indicates engine family ('2' for M272 series). Pre-2009 models have silver valve covers with ribbed finish; post-2009 units use black valve covers. Critical differentiation from M272.920: Original M272.921 has Bosch ME 2.8 ECU with 80-pin connector, while M272.920 uses ME 9.7 with 104-pin. Service parts require production date verification - cam adjusters for engines before 09/2008 are incompatible with later units due to internal redesign (Mercedes-Benz SIB 02.2010.02).
The M272.921's primary reliability risk is intake camshaft adjuster wear on early builds, with elevated incidence in urban driving and extended oil intervals. Internal Mercedes-Benz quality reports from 2011 indicated a significant portion of pre-2009 engines required adjuster replacement before 150,000 km, while UK DVSA records show a notable share of emissions-related MOT failures linked to catalytic converter degradation in city-driven vehicles. Frequent cold starts and low-RPM operation increase valve train stress, making oil quality and interval adherence critical.
Analysis derived from Mercedes-Benz technical bulletins (2008–2013) and UK DVSA failure statistics (2014–2022). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ M272921.
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