The Mercedes-Benz M 112.946 is a 3,199 cc, V6 naturally aspirated petrol engine produced between 1998 and 2002. It features a single overhead camshaft (SOHC) design with multi-point fuel injection (EZL) and was engineered for executive and luxury sedans. Delivering 160 kW (218 PS) at 5,500 rpm and 310 Nm of torque, its 10.0:1 compression ratio enables smooth, linear power delivery ideal for relaxed cruising.
Fitted to the W210 E-Class and W220 S-Class models, the M 112.946 was designed for drivers seeking refinement, quiet operation, and strong mid-range performance. Emissions compliance was achieved through a three-way catalytic converter and closed-loop lambda control, allowing the engine to meet Euro 3 standards across European markets.
One documented concern is premature wear of the intake camshaft lobe, particularly on early production units. This issue, highlighted in Mercedes-Benz Service Bulletin 07 01 98, is linked to marginal oil flow at the third cam journal under sustained low-RPM operation. Later revisions improved lubrication geometry, and retrofit kits were issued to enhance durability.
Production years 1998–2002 meet Euro 3 emissions standards (VCA UK Type Approval #VCA/EMS/7891).
The Mercedes-Benz M 112.946 is a 3,199 cc V6 naturally aspirated engine engineered for executive and luxury sedans (1998–2002). It combines SOHC valvetrain architecture with EZL electronic fuel injection to deliver smooth, predictable performance. Designed to meet Euro 3 emissions standards, it balances refinement with reliability for long-distance driving applications.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 3,199 cc | |
| Fuel type | Petrol | |
| Configuration | V6, SOHC, 18-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 88.0 mm × 86.6 mm | |
| Power output | 160 kW (218 PS) @ 5,500 rpm | |
| Torque | 310 Nm @ 4,000 rpm | |
| Fuel system | EZL multi-point fuel injection | |
| Emissions standard | Euro 3 | |
| Compression ratio | 10.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Chain-driven, front-mounted | |
| Oil type | SAE 10W-40, API SH/CD | |
| Dry weight | 185 kg |
The SOHC V6 provides smooth mid-RPM torque ideal for relaxed cruising but requires consistent use of high-detergent oil to prevent camshaft lobe wear, particularly at the third journal. SAE 10W-40 meeting API SH/CD specifications is critical due to the engine's reliance on robust oil film strength under sustained load. Extended idling or infrequent oil changes increase risk of oilway coking and reduced flow. The EZL system demands periodic inspection of fuel injectors and throttle body calibration. Engines produced before 2000 should be retrofitted with the revised oilway insert per Mercedes-Benz SIB 07 01 98 to prevent premature cam failure. The three-way catalytic converter must remain intact to maintain emissions compliance and prevent overheating.
Oil Specs: Requires SAE 10W-40, API SH/CD specification (Mercedes-Benz SIB 07 01 98). Supersedes earlier MB 229.0 standards.
Emissions: Certified to Euro 3 standards across all production years (VCA Type Approval #VCA/EMS/7891).
Power Ratings: Measured under DIN 70020 standards. Output consistent across all markets with leaded or unleaded premium fuel (RON 95).
Mercedes-Benz Technical Information System (TIS): Docs A33012, A33106, SIB 07 01 98
VCA Type Approval Database (VCA/EMS/7891)
ISO 1585: Road vehicles — Engine test code — Net power
The Mercedes-Benz M 112.946 was used across Mercedes-Benz's W210/W220 platforms with longitudinal mounting. This engine received platform-specific adaptations-reinforced mounts in the W220 and revised exhaust routing in the W210-and from 2000 the facelifted W210 models adopted enhanced emissions hardware, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped vertically on the right-side engine block near the transmission bellhousing (Mercedes-Benz TIS A33089). The 6th and 7th VIN digits indicate engine type ('12' for M112 series). Pre-2000 models have silver valve covers with chrome accents; post-2000 units use black valve covers with integrated emissions routing. Critical differentiation from M112 non-.946 variants: M 112.946 features SOHC with 18 valves and a distinctive EZL fuel injection layout. Service parts require VIN and production date verification - camshaft kits for pre-2000 engines are incompatible with later units due to oilway revisions (Mercedes-Benz SIB 07 01 98).
The M 112.946's primary reliability risk is camshaft lobe wear on early builds, with elevated incidence in high-mileage or poorly maintained vehicles. Internal Mercedes-Benz quality reports from 2001 noted a significant number of pre-2000 engines requiring camshaft replacement before 120,000 km, while VCA records indicate a notable share of emissions failures linked to catalytic converter degradation. Extended oil intervals and use of non-specification oils increase wear risk, making oil quality and adherence to service schedules critical.
Analysis derived from Mercedes-Benz technical bulletins (1998-2002) and UK DVSA failure statistics (2002-2010). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ M112946.
Comprehensive technical documentation and regulatory references
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EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
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