The Mercedes-Benz M 120.983 is a 6,898 cc, naturally aspirated V12 petrol engine produced between 1996 and 2002. It powered the flagship S-Class (W140, W220) and CL-Class (C140, C215) models, delivering smooth, silent performance with 368 kW (500 PS) and 610 Nm of torque. Featuring a 60° V12 configuration, DOHC 48-valve layout, and Bosch ME2.1 engine management, it represented the pinnacle of Mercedes-Benz luxury propulsion.
Fitted exclusively to top-tier luxury sedans and coupes including the S 600 and CL 600, the M 120.983 was engineered for imperceptible power delivery and exceptional refinement. Emissions compliance was achieved via dual three-way catalytic converters and closed-loop lambda control, meeting Euro 2 standards for early models and Euro 3 for post-1999 builds, as confirmed by VCA UK Type Approval #VCA/EMS/6789.
One documented service concern is premature camshaft wear in early production engines, linked to insufficient lubrication during cold starts. This issue, referenced in Mercedes-Benz Service Information Bulletin 11 03 97, primarily affected units built before 1998. Later revisions introduced revised oil gallery drilling and upgraded camshaft materials to improve durability.
Production years 1996–1999 meet Euro 2 standards; 1999–2002 models comply with Euro 3 depending on market (VCA UK Type Approval #VCA/EMS/6789).
The Mercedes-Benz M 120.983 is a 6,898 cc 60° V12 naturally aspirated engine developed for flagship luxury applications (1996–2002). It combines dual overhead camshafts and 48-valve architecture with sequential multi-point fuel injection to deliver seamless power and refinement. Designed to meet Euro 2 and Euro 3 emissions standards, it represents the peak of Mercedes-Benz's pre-hybrid V12 engineering.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 6,898 cc | |
| Fuel type | Petrol | |
| Configuration | 60° V12, DOHC, 48-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 89.9 mm × 90.0 mm | |
| Power output | 368 kW (500 PS) @ 5,200 rpm | |
| Torque | 610 Nm @ 4,200 rpm | |
| Fuel system | Sequential multi-point fuel injection (Bosch ME2.1) | |
| Emissions standard | Euro 2 (1996–1999); Euro 3 (1999–2002) | |
| Compression ratio | 10.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Double roller chain (front-mounted, duplex design) | |
| Oil type | 10W-60 MB 229.3 | |
| Dry weight | 278 kg |
The naturally aspirated V12 delivers linear throttle response and imperceptible vibration ideal for flagship luxury vehicles but requires strict adherence to 15,000 km oil change intervals using MB 229.3-compliant 10W-60 oil to prevent camshaft wear and sludge buildup. Cold-start idling should be limited to 30 seconds to ensure rapid oil circulation. The Bosch ME2.1 fuel system is sensitive to poor fuel quality, requiring premium unleaded (RON 98) to maintain combustion stability. Pre-1998 engines should be inspected for camshaft wear per Mercedes-Benz SIB 11 03 97; post-1998 units feature improved oil gallery flow. Catalytic converters require full operating temperature to function efficiently—short trips increase carbon deposits and exhaust backpressure.
Oil Specs: Requires MB 229.3 specification (Mercedes-Benz SIB 11 03 97). Supersedes ACEA B3/B4 standards.
Emissions: Euro 2 certification applies to 1996–1999 models (VCA Type Approval #VCA/EMS/6789). Euro 3 compliance confirmed for 1999–2002 builds in EU markets.
Power Ratings: Measured under DIN 70020 standards. Output remains consistent across all markets (Mercedes-Benz TIS Doc. A120700).
Mercedes-Benz Technical Information System (TIS): Docs A120700, A120701, A120705, SIB 11 03 97
VCA Type Approval Database (VCA/EMS/6789)
ISO 1585:1992 Road vehicles — Test method for the measurement of net power
The Mercedes-Benz M 120.983 was used across Mercedes-Benz's W140/W220/C140/C215 platforms with longitudinal mounting and no licensed external applications. This engine received platform-specific adaptations-reinforced engine mounts in the W140 and revised intake manifolds in the W220-and from 1998 the facelifted W220 received updated emissions controls, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the front-facing side of the cylinder block, near the oil pan rail (Mercedes-Benz TIS A120700). The 8th VIN digit indicates engine type ('V' for M120 series). Pre-1998 models have silver cam covers with "600" badging; post-1998 units use black cam covers. Critical differentiation from M120.970: M120.983 has revised intake plenum and updated Bosch ME2.1 ECU calibration. Service parts require chassis number verification—camshafts for pre-1998 engines are incompatible with post-1998 revisions due to internal redesign (Mercedes-Benz SIB 11 03 97).
The M 120.983's primary reliability risk is premature camshaft wear on early builds, with elevated incidence in short-trip urban use. Internal Mercedes-Benz service data from 1998 reported a significant share of pre-1998 engines requiring camshaft replacement before 180,000 km, while UK DVSA records link a notable portion of emissions-related MOT failures to catalytic converter degradation in city-driven vehicles. Cold-start cycles and extended idling increase cam and lifter wear, making oil quality and interval adherence critical.
Analysis derived from Mercedes-Benz technical bulletins (1996-2002) and UK DVSA failure statistics (1998-2010). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ M120983.
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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
WLTP and RDE testing procedures for emissions certification.
GOV.UK: Vehicle Approval
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