The Mercedes-Benz M 276.821 is a 2,996 cc, V6 petrol engine produced between 2012 and 2017. It features dual overhead camshafts (DOHC), variable valve timing (VVT) on both intake and exhaust, and direct fuel injection with spray-guided combustion. In standard tune it delivered 200 kW (272 PS) and 370 Nm of torque, offering a balance of responsive performance and fuel efficiency for executive and performance applications.
Fitted to key models including the W204 C-Class, W212 E-Class, and W218 CLS-Class, the M 276.821 was engineered for dynamic driving and refined power delivery. It met Euro 6 emissions standards using a three-way catalytic converter, exhaust gas recirculation (EGR), and advanced engine management, with cylinder deactivation introduced in later variants to enhance efficiency.
One documented concern is premature wear of the high-pressure fuel pump (HPFP) drive shaft, noted in Mercedes-Benz Service Bulletin 12.2014. This issue, linked to torsional vibrations in the timing chain system, can lead to fuel delivery faults and engine stalling. From 2015, revised pump drive components and upgraded chain dampers were implemented to mitigate the risk.
All models meet Euro 6b standards; 2015–2017 units with cylinder deactivation comply with Euro 6c (VCA UK Type Approval #VCA/EMS/7421).
The Mercedes-Benz M 276.821 is a 2,996 cc V6 petrol engine developed for executive and performance platforms (2012–2017). It combines direct injection with variable valve timing to deliver smooth power delivery and strong mid-range torque. Designed to meet Euro 6b (and select Euro 6c) standards, it balances performance with emissions compliance.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,996 cc | |
| Fuel type | Petrol | |
| Configuration | 60° V6, DOHC, 24-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 88.0 mm × 82.1 mm | |
| Power output | 200 kW (272 PS) @ 6,500 rpm | |
| Torque | 370 Nm @ 3,500–5,250 rpm | |
| Fuel system | Direct injection (spray-guided, up to 200 bar) | |
| Emissions standard | Euro 6b; Euro 6c with cylinder deactivation (2015–2017) | |
| Compression ratio | 11.3:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Double-row roller chain with hydraulic tensioner | |
| Oil type | MB 229.51 (SAE 0W-40) | |
| Dry weight | 184 kg |
The naturally aspirated V6 provides linear power delivery ideal for relaxed driving but requires adherence to 15,000 km oil change intervals using MB 229.51 specification oil to ensure longevity of the high-pressure fuel pump and hydraulic lifters. Cold-start idling should be limited to 30 seconds to ensure prompt oil circulation. Direct injection increases carbon buildup on intake valves; intake cleaning is recommended every 60,000 km. Post-2015 models feature revised HPFP drive and chain damper; pre-2015 units should be inspected per Mercedes-Benz SIB 12 2014. EGR systems require cleaning every 80,000 km to prevent flow restriction and fault codes.
Oil Specs: Requires MB 229.51 (0W-40) specification (Mercedes-Benz SIB 12 2014). Compatible with ACEA C2 but not C3.
Emissions: Euro 6b certification applies to all models. Euro 6c compliance confirmed for 2015–2017 units with cylinder deactivation (VCA Type Approval #VCA/EMS/7421).
Power Ratings: Measured under ECE R15-03 standards. Output consistent across fuel qualities meeting EN 228 RON 95 minimum.
Mercedes-Benz Technical Information System (TIS): Docs A33580, A33701, SIB 12 2014
VCA Type Approval Database (VCA/EMS/7421)
ECE Regulation 15-03: Emissions Measurement Standards
The Mercedes-Benz M 276.821 was used across Mercedes-Benz's W204, W212, and W218 platforms with longitudinal mounting and no licensed external applications. This engine received platform-specific adaptations-shortened accessory drives in the W204 and reinforced engine mounts in the W218-and from 2015 the facelifted W212 models adopted revised high-pressure fuel pump drives, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the front of the cylinder block, near the timing cover (Mercedes-Benz TIS A33580). The 7th VIN digit indicates engine family ('G' for M 276 series). Pre-2015 models have silver cam covers with black plastic intake manifolds; post-2015 units use black cam covers. Critical differentiation from M 272: M 276.821 has a twin-pipe exhaust manifold and lacks balance shafts. Service parts require production date verification—high-pressure fuel pumps before 06/2015 are incompatible with later units due to drive shaft redesign (Mercedes-Benz SIB 12 2014).
The M 276.821's primary reliability risk is high-pressure fuel pump drive wear on early builds, with elevated incidence in stop-start urban use. Internal Mercedes-Benz quality reports from 2016 indicated a notable share of pre-2015 engines required HPFP replacement before 130,000 km, while UK DVSA records show fuel system-related faults contribute to emissions test failures in city-driven vehicles. Frequent cold starts and extended idling increase torsional stress on the drive mechanism, making oil quality and interval adherence critical.
Analysis derived from Mercedes-Benz technical bulletins (2013-2017) and UK DVSA failure statistics (2018-2022). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ M276821.
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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