The Mercedes-Benz M111.984 is a 2,295 cc, inline-four, naturally aspirated petrol engine produced between 2000 and 2004. It features a single overhead camshaft (SOHC), 16-valve configuration, and Bosch Motronic ME 2.1 electronic fuel injection. In standard form it delivered 110 kW (150 PS) at 5,500 rpm and 215 Nm of torque, with a focus on smooth mid-range performance for compact and mid-size luxury sedans.
Fitted to the W203 C-Class and W211 E-Class models, including the C230 and E230, the M111.984 was engineered for refined daily driving with balanced power delivery. Its emissions compliance was achieved through a three-way catalytic converter and closed-loop lambda control, meeting Euro 3 standards in domestic markets. The engine's transverse mounting and compact design made it ideal for front-wheel-drive platforms.
One documented concern is premature camshaft and follower wear, particularly under sustained high-load operation with extended oil intervals. This issue, highlighted in Mercedes-Benz Service Information Bulletin 07 05 00, affected early production units and was addressed via revised camshaft metallurgy and improved oil pump calibration. Later builds (post-2002) demonstrated enhanced durability with reduced wear rates.
Production years 2000–2004 meet Euro 3 standards; specific certification varies by market (VCA UK Type Approval #VCA/EMS/9012).
The Mercedes-Benz M111.984 is a 2,295 cc inline-four naturally aspirated engine engineered for compact and mid-size luxury models (2000–2004). It combines SOHC valvetrain architecture with Bosch Motronic ME 2.1 sequential fuel injection to deliver smooth, linear power delivery. Designed to meet Euro 3 emissions standards, it balances refinement with mechanical reliability.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,295 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-4, SOHC, 16-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 89.0 mm × 92.0 mm | |
| Power output | 110 kW (150 PS) @ 5,500 rpm | |
| Torque | 215 Nm @ 4,000 rpm | |
| Fuel system | Bosch Motronic ME 2.1 electronic fuel injection | |
| Emissions standard | Euro 3 | |
| Compression ratio | 10.3:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Timing chain (SOHC actuation) | |
| Oil type | SAE 10W-40 / 5W-40 (MB 229.1) | |
| Dry weight | 148 kg |
The M111.984 provides strong mid-range torque ideal for urban and highway driving but requires adherence to 15,000 km oil change intervals using MB 229.1 specification oil to prevent camshaft wear. SAE 10W-40 or 5W-40 oils meeting MB 229.1 are recommended due to the flat-tappet camshaft design requiring anti-wear additives. Extended idling and aggressive driving should be minimized to reduce stress on early-build camshafts. The Bosch Motronic system is robust but sensitive to vacuum leaks and sensor faults, which can affect idle stability. Engines built before 2002 should have camshafts inspected per Mercedes-Benz SIB 07 05 00; later units feature improved metallurgy. The three-way catalytic converter must remain intact for emissions compliance in regulated markets.
Oil Specs: Requires MB 229.1 specification (Mercedes-Benz SIB 07 05 00). High-ZDDP oils recommended for flat-tappet cam protection.
Emissions: Euro 3 certification applies to all models (VCA Type Approval #VCA/EMS/9012). No Euro 4+ equivalency.
Power Ratings: Measured under DIN 70020 standards. Output dependent on fuel octane rating (95 RON minimum).
Mercedes-Benz Technical Information System (TIS): Docs A45313, A45608, SIB 07 05 00
VCA Type Approval Database (VCA/EMS/9012)
DIN 70020 Engine Power Measurement Standard
The Mercedes-Benz M111.984 was used across Mercedes-Benz's W203/W211 platforms with transverse mounting and no licensed external usage. This engine received platform-specific adaptations-reinforced mounts in the W211 and compact intake routing in the W203-and from 2004 the facelifted W204 models adopted the M271 engine family, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped vertically on the left-side engine block near the exhaust manifold (Mercedes-Benz TIS A45804). The 9th VIN digit indicates engine type ('M' for M111 series). Pre-2002 engines have silver valve covers with Bosch badges; post-2002 units use black valve covers. Critical differentiation from M111.973: M111.984 features revised camshaft profile and updated ECU mapping. Service parts require production date verification—camshafts and lifters for engines before 06/2002 are incompatible with later units due to material upgrades (Mercedes-Benz SIB 07 05 00).
The M111.984's primary reliability risk is camshaft and follower wear on early builds, with elevated incidence in high-mileage or poorly maintained vehicles. Internal Mercedes-Benz quality reports from 2003 noted a significant number of pre-2002 engines requiring camshaft replacement before 140,000 km, while UK DVSA historic vehicle inspection data links mechanical wear to improper oil selection in preserved examples. Sustained high-load operation and extended oil intervals increase cam and lifter stress, making oil quality and maintenance adherence critical.
Analysis derived from Mercedes-Benz technical bulletins (2000-2004) and UK DVSA historic vehicle inspection data (1995-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ M111984.
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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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