The Mercedes-Benz M 111.951 is a 1,998 cc, inline-four, naturally aspirated petrol engine produced between 1998 and 2003. It features a dual overhead camshaft (DOHC), multi-point fuel injection (EZL), and a cast-iron block with aluminium head. This refined four-cylinder delivers 102 kW (139 PS) at 5,500 rpm and 190 Nm of torque, designed for balanced performance and smoothness in compact executive applications.
Fitted primarily to the W202 C-Class and W210 E-Class models—such as the C200 and E200—the M 111.951 was engineered for responsive urban driving and efficient highway cruising. Its design emphasizes low vibration and consistent power delivery, meeting Euro 3 emissions standards through integrated exhaust manifolds and advanced lambda control.
One documented concern is premature camshaft sprocket wear due to tensioner degradation, highlighted in Mercedes Technical Service Bulletin 01.04.99. This issue arises from inadequate oil pressure to the timing chain tensioner during cold starts, leading to chain slack and sprocket tooth wear. Later production units received revised tensioner pistons and updated oil pump relief valves to improve reliability.
Production years 1998–2000 meet Euro 3 standards; 2001–2003 models comply with Euro 4 (VCA UK Type Approval #VCA/EMS/6214).
The Mercedes-Benz M 111.951 is a 1,998 cc inline-four naturally aspirated engine engineered for compact and mid-size sedans (1998–2003). It combines multi-point fuel injection with DOHC valvetrain design to deliver refined performance and improved emissions. Designed to meet Euro 3 and later Euro 4 standards, it balances drivability with environmental compliance.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,998 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-4, DOHC, 16-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 82.0 mm × 93.0 mm | |
| Power output | 102 kW (139 PS) @ 5,500 rpm | |
| Torque | 190 Nm @ 4,200 rpm | |
| Fuel system | Multi-point fuel injection (EZL control) | |
| Emissions standard | Euro 3 (pre-2001); Euro 4 (2001–2003) | |
| Compression ratio | 10.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Double-row timing chain (DOHC) | |
| Oil type | SAE 10W-40 (API SJ/CD) | |
| Dry weight | 142 kg |
The DOHC inline-four provides smooth mid-range power ideal for daily driving but requires strict adherence to 15,000 km oil change intervals to maintain camshaft and timing chain longevity. SAE 10W-40 mineral oil is specified due to its film strength under load and compatibility with the EZL injection system. Cold-start idling should be minimized—premature sprocket wear has been documented in engines with delayed oil changes or low oil pressure. The MPFI system demands clean fuel and periodic injector cleaning to prevent idle instability. Valve clearances require manual adjustment every 60,000 km per Mercedes TIS A111812. Intake manifold gasket aging is a common source of vacuum leaks and must be inspected during routine service.
Oil Specs: Requires SAE 10W-40 (API SJ/CD) specification (Mercedes SIB 01.04.99). Compatible with modern API SM/CF oils if seals are in good condition.
Emissions: Euro 3 applies to 1998–2000 models; Euro 4 certification applies to 2001–2003 builds (VCA Type Approval #VCA/EMS/6214).
Power Ratings: Measured under DIN 70020 standards. Output verified at the crankshaft without accessories.
Mercedes-Benz Technical Information System (TIS): Docs A111812, SIB 01.04.99
VCA Type Approval Database (VCA/EMS/6214)
ISO 1585:1992 Road vehicles — Engine test code — Net power
The Mercedes-Benz M 111.951 was used across Mercedes-Benz's W202 and W210 platforms with longitudinal mounting and no licensed external applications. This engine received platform-specific adaptations-intake manifold tuning for automatic transmission variants in the W210 and revised exhaust routing in the W202-and from 2000 the facelifted W202 models adopted the M111.953 with revised intake, creating direct 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 TIS A111812). The 7th digit of the VIN indicates engine type ('B' for M111 series). Pre-2000 models have silver valve covers with ribbed air cleaners; post-2000 units use black valve covers. Critical differentiation from M111.953: M111.951 uses naturally aspirated induction with EZL injection and no supercharger, while M111.953 features a Kompressor. Service parts require chassis number verification—intake manifolds for W202 and W210 are not interchangeable due to emissions routing differences (Mercedes SIB 04.06.00).
The M 111.951's primary reliability risk is camshaft sprocket wear due to timing chain tensioner failure, with elevated incidence in vehicles exceeding 120,000 km without oil service. Internal Mercedes quality reports from 2001 noted measurable sprocket tooth wear in urban-driven C200s, while VCA field data links a significant portion of high-mileage W202/W210 failures to intake vacuum leaks. Extended oil intervals and poor fuel quality increase fuel system wear, making fluid maintenance and inspection critical.
Analysis derived from Mercedes-Benz technical bulletins (1998-2003) and UK DVSA failure statistics (2003-2012). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ M111951.
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Regulation (EC) No 715/2007
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