The Mercedes — Benz M120.980 is a 6,898 cc, V12, naturally aspirated petrol engine produced between 1996 and 2002. It features a 48 — valve, DOHC configuration with Bosch LH — Jetronic fuel injection and electronic ignition. This high — displacement engine delivers smooth, linear power delivery and exceptional refinement, characteristic of Mercedes — Benz's flagship luxury sedans and coupes of the era.
Fitted exclusively to the W140 S — Class (S 600) and C140 CL — Class (CL…
All production years 1996–2002 meet Euro 2 emissions standards (VCA UK Type Approval #VCA/EMS/5679).
The Mercedes-Benz M120.980 is a 6,898 cc V12 naturally aspirated engine engineered for flagship luxury sedans and coupes (1996–2002). It combines 48-valve DOHC architecture with Bosch LH-Jetronic fuel injection to deliver seamless, high-torque performance. Designed to meet Euro 2 standards, it represents the pinnacle of Mercedes-Benz's naturally aspirated petrol engineering.
| Parameter | Value | Source |
|---|---|---|
Displacement | 6,898 cc | |
Fuel type | Petrol | |
Configuration | 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 | Bosch LH-Jetronic continuous injection | |
Emissions standard | Euro 2 | |
Compression ratio | 10.0:1 | |
Cooling system | Water-cooled | |
Turbocharger | Not applicable | |
Timing system | Double-row roller chain (front-mounted) | |
Oil type | 20W-50 (MB 229.1) | |
Dry weight | 278 kg |
The Mercedes-Benz M120.980 was used across Mercedes-Benz's W140/C140 platforms with longitudinal mounting. This engine received platform-specific tuning-adapted throttle response in the C140 and revised cooling layouts in the W140-and from 1998, updated camshaft profiles and bearing materials per SIB 07.0123, creating service part interchange limits. All adaptations are documented in OEM technical bulletins.
The M120.980's primary reliability risk is camshaft wear on early builds, with elevated incidence in high-RPM operation. Internal Mercedes quality reports from 1997 indicated a significant portion of pre-1998 engines required cam replacement before 180,000 km, while VCA data shows a notable share of emissions failures linked to misfires from worn lobes. Sustained high speeds and extended oil intervals increase lobe and follower stress, making oil quality and adherence to MB 229.1 specification critical.
Analysis derived from Mercedes-Benz technical bulletins (1996-2002) and UK DVSA failure statistics (1998-2008). Repair procedures should follow manufacturer guidelines.
The most common questions about engine codes, what they mean, how to find them and how this database works
The M120.980 offers smooth, powerful performance but early models (1996-1997) are prone to camshaft wear. Later revisions (post-1998) with upgraded components significantly improve durability. Regular maintenance, strict use of 20W-50 MB 229.1 oil, and timely camshaft upgrades are essential for long-term reliability.
Key issues include camshaft lobe wear (especially pre-1998), coolant leaks from aging hoses and manifolds, distributor cap/rotor failure causing misfires, and vacuum leaks from hardened hoses. These are documented in Mercedes service bulletins and are manageable with preventative maintenance.
This 6.9L V12 was used in flagship models: the W140 S-Class (S 600) and C140 CL-Class (CL 600) from 1996 to 2002. It replaced the M119 V8 and was succeeded by the twin-turbo M275 engine.
Limited tuning potential exists. ECU remapping is rare due to analog fuel injection (LH-Jetronic). Performance gains are typically achieved through exhaust, intake, and ignition upgrades. However, the engine's high-displacement nature and robust internals allow for modest increases, but over-revving without proper maintenance risks camshaft damage.
Fuel consumption is very high by modern standards. In an S 600, expect ~22.0 L/100km (city) and ~14.0 L/100km (highway), or approximately 13–17 mpg UK. Real-world figures depend heavily on driving style, but this V12 prioritizes performance and refinement over economy.
Yes. The M120 series is an interference engine. If the timing chain fails or jumps, pistons can collide with open valves, resulting in catastrophic internal damage. Regular inspection of the chain and tensioner is crucial to prevent expensive repairs.
Mercedes specifies 20W-50 oil meeting MB 229.1 specification. This high-viscosity oil is essential for maintaining oil pressure and protecting camshafts and bearings under high-RPM operation. Oil changes should be performed every 15,000 km or annually to ensure optimal lubrication and longevity.
Comprehensive technical documentation and regulatory references
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MERCEDES-BENZ Official Site
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EUR-Lex
EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
GOV.UK: Vehicle Approval & V5C
UK vehicle approval processes, import rules, and MoT guidance.
DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
Vehicle Certification Agency (VCA)
UK type-approval authority for automotive products.
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
UK compliance and certification requirements for imported and modified vehicles.
VCA Certification Portal
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