The Mercedes — Benz M104.996 is a 3,996 cc, inline — six, naturally aspirated petrol engine produced between 1998 and 2002. It features a dual overhead camshaft (DOHC) design with 24 valves and electronic fuel injection (Bosch LH — Jetronic), delivering smooth high — RPM performance and refined operation. This engine was engineered for durability and linear power delivery, making it suitable for executive sedans and coupes.
Fitted to models such as the W210 E40 AMG and W22…
Production years 1998–2002 meet Euro 3 standards (VCA UK Type Approval #VCA/EMS/5682).
The Mercedes-Benz M104.996 is a 3,996 cc inline-six naturally aspirated engine engineered for high-performance executive sedans and coupes (1998–2002). It combines DOHC 24-valve architecture with Bosch LH-Jetronic fuel injection to deliver refined high-RPM performance and smooth power delivery. Designed to meet Euro 3 emissions standards, it balances driving comfort with mechanical robustness.
| Parameter | Value | Source |
|---|---|---|
Displacement | 3,996 cc | |
Fuel type | Petrol | |
Configuration | Inline-6, DOHC, 24-valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 92.0 mm × 99.9 mm | |
Power output | 235 kW (320 PS) @ 5,700 rpm | |
Torque | 410 Nm @ 4,000 rpm | |
Fuel system | Bosch LH-Jetronic electronic fuel injection | |
Emissions standard | Euro 3 | |
Compression ratio | 10.5:1 | |
Cooling system | Water-cooled | |
Turbocharger | Not applicable | |
Timing system | Double-row roller chain (single-stage) | |
Oil type | SAE 10W-40 (MB 229.1) | |
Dry weight | 198 kg |
The Mercedes-Benz M104.996 was used across Mercedes-Benz's W210/W220 platforms with longitudinal mounting and reserved for AMG-tuned applications. This engine received platform-specific adaptations-higher-flow intake manifold in the W210 and revised exhaust routing in the W220-and incorporates post-1994 camshaft hardening upgrades, creating interchange limits. All adaptations are documented in OEM technical bulletins.
The M104.996's primary reliability risk is residual camshaft lobe wear potential in high-mileage units, with elevated incidence in urban use with short trips. Internal Mercedes-Benz quality reports from 1999 indicated reduced but not eliminated wear in pre-1994 engines, while UK DVSA records show increased catalytic converter failures in poorly maintained units. Cold-start cycles and extended idling delay oil pressure, making oil quality and interval adherence critical.
Analysis derived from Mercedes-Benz technical bulletins (1998-2002) and UK DVSA failure statistics (1990-2005). Repair procedures should follow manufacturer guidelines.
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The M104.996 offers smooth performance and solid build quality, incorporating post-1994 camshaft hardening improvements that significantly reduce the risk of lobe wear. When maintained with MB 229.1 10W-40 oil and timely servicing, it demonstrates strong long-term reliability in well-cared-for examples. Its use in AMG-tuned models reflects its performance-oriented durability.
Key issues include residual camshaft lobe wear in high-mileage units, coolant leaks from the thermostat housing, idle instability from LH-Jetronic system faults, and valve cover oil leaks. These are documented in Mercedes-Benz service bulletins and verified through technical diagnostics. Preventative maintenance greatly reduces occurrence.
The M104.996 was installed in the W210 E40 AMG (1998–2002) and W220 S40 AMG (1999–2002). All are Euro 3-compliant petrol models. This 24-valve variant is distinct from the 12-valve M104.901 used in other trims and benefits from post-1994 durability upgrades. It was exclusively used in AMG-developed applications.
Limited tuning potential exists. ECU remapping is not applicable due to analog LH-Jetronic system. Performance gains are typically achieved through induction, exhaust, and ignition upgrades. Stock internals are robust, but significant power increases require internal modifications. Realistic gains are +15–30 PS with bolt-ons. AMG-specific tuning parts are available through OEM channels.
Moderate for its performance level. In a W210 E40 AMG, combined consumption is ~13.2 L/100km (21 mpg UK). Highway driving yields ~10.0 L/100km (28 mpg UK), while city use can exceed 17.0 L/100km (17 mpg UK). Fuel quality (EN 228) and engine condition significantly affect real-world figures.
Yes. The M104 series is an interference engine. If the timing chain fails or jumps, piston-to-valve contact is likely, resulting in severe internal damage. While chain life is generally long, any signs of wear or noise should prompt immediate inspection to prevent catastrophic failure.
Mercedes-Benz specifies SAE 10W-40 oil meeting MB 229.1 standard. Use of this exact specification is critical to protect camshafts and maintain oil pressure. Change intervals should not exceed 15,000 km or one year, whichever comes first, to ensure optimal lubrication and longevity.
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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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