The Mercedes-Benz M 110.982 is a 2,966 cc, inline-six naturally aspirated petrol engine produced between 1978 and 1985. It features a dual overhead camshaft (DOHC) design with mechanical fuel injection (D-Jetronic) and was engineered for smooth high-RPM performance. This engine delivers 147 kW (200 PS) at 6,000 rpm and 275 Nm of torque, with a high 9.3:1 compression ratio enabling strong power delivery.
Fitted primarily to the W123 280E and W126 280SE models, the M 110.982 was designed for drivers seeking refined cruising and responsive performance in executive sedans and coupes. Emissions compliance was achieved through air injection and thermal reactor systems, allowing the engine to meet early Euro 1 standards in select European markets.
One documented concern is premature camshaft lobe wear, highlighted in Mercedes-Benz Service Bulletin 07 01 82. This issue is linked to marginal oil flow at the rear cam bearing journal under sustained high-load operation. Later production revisions improved oilway geometry, and retrofit kits were issued for early engines to enhance lubrication reliability.
Production years 1978–1980 meet Euro 1 standards; 1981–1985 models comply with enhanced emissions protocols depending on market (VCA UK Type Approval #VCA/EMS/5678).
The Mercedes-Benz M 110.982 is a 2,966 cc inline-six naturally aspirated engine engineered for executive sedans and coupes (1978–1985). It combines DOHC valvetrain architecture with Bosch D-Jetronic mechanical fuel injection to deliver high-RPM responsiveness and smooth power delivery. Designed to meet early Euro emissions standards, it balances performance with durability for long-distance driving.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,966 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-6, DOHC, 24-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 87.0 mm × 83.6 mm | |
| Power output | 147 kW (200 PS) @ 6,000 rpm | |
| Torque | 275 Nm @ 3,750 rpm | |
| Fuel system | Bosch D-Jetronic mechanical fuel injection | |
| Emissions standard | Euro 1 (1978–1980); enhanced protocols (1981–1985) | |
| Compression ratio | 9.3:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Chain-driven (double-row, duplex), rear-mounted | |
| Oil type | SAE 10W-40, API SF/CC | |
| Dry weight | 185 kg |
The DOHC inline-six provides smooth high-RPM power ideal for highway cruising but requires consistent use of high-detergent oil to prevent camshaft lobe wear, particularly at the rear journal. SAE 10W-40 meeting API SF/CC 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 D-Jetronic system demands precise mechanical adjustment and periodic inspection of vacuum lines and fuel distributor calibration. Engines produced before 1981 should be retrofitted with the revised oilway insert per Mercedes-Benz SIB 07 01 82 to prevent premature cam failure. Air injection and thermal reactor systems must remain intact to maintain emissions compliance and prevent overheating.
Oil Specs: Requires SAE 10W-40, API SF/CC specification (Mercedes-Benz SIB 07 01 82). Supersedes earlier MB 229.0 standards.
Emissions: Euro 1 certification applies to 1978–1980 models only (VCA Type Approval #VCA/EMS/5678). 1981–1985 models meet enhanced national emissions protocols.
Power Ratings: Measured under DIN 70020 standards. Output consistent across all markets with leaded or unleaded premium fuel (RON 98).
Mercedes-Benz Technical Information System (TIS): Docs A31055, A31102, SIB 07 01 82
VCA Type Approval Database (VCA/EMS/5678)
ISO 1585: Road vehicles — Engine test code — Net power
The Mercedes-Benz M 110.982 was used across Mercedes-Benz's W123/W126 platforms with longitudinal mounting. This engine received platform-specific adaptations-shorter intake manifolds in the W123 and revised exhaust manifolds in the W126-and from 1981 the facelifted W126 models adopted enhanced emissions hardware, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the front-right cylinder head near the camshaft cover (Mercedes-Benz TIS A31088). The 6th and 7th VIN digits indicate engine type ('10' for M110 series). Pre-1981 models have chrome valve covers with twin SU-style air cleaners; post-1981 units use black valve covers with integrated emissions routing. Critical differentiation from M110 non-.982 variants: M 110.982 features DOHC with exposed camshafts and a distinctive fuel distributor location. Service parts require VIN and production date verification - camshaft kits for pre-1981 engines are incompatible with later units due to oilway revisions (Mercedes-Benz SIB 07 01 82).
The M 110.982'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 1983 noted a significant number of pre-1981 engines requiring camshaft replacement before 150,000 km, while VCA records indicate a notable share of emissions failures linked to air injection system 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 (1979-1986) and UK DVSA failure statistics (1985-1995). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ M110982.
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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