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 .
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 | Refer to vehicle handbook / manufacturer specification | |
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.
Engine Finders UK Ltd, which operates EngineCode.uk, can pass your enquiry to engine suppliers in the UK. The service is for vehicles in the United Kingdom, with UK delivery or fitting. This is a commercially connected service, and sending an enquiry does not confirm diagnosis or compatibility.
Diagnostic reminder: If a technician has recommended replacing the engine, you can send an enquiry to engine suppliers in the UK. Confirm the diagnosis first: an engine-code record does not diagnose a fault.
Field reports and technical service bulletins highlight component wear patterns under high-load operation. Adherence to manufacturer service intervals and approved fluid specifications is critical for long-term reliability.
Analysis derived from manufacturer technical service bulletins and industry workshop records. 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 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.
Comprehensive technical documentation and regulatory references
EngineCode.uk is operated by Engine Finders UK Ltd. It provides engine-reference information and an optional commercial enquiry service. It is not an official manufacturer website. Check the record's sources and confirm vehicle-specific details before relying on it for parts, repairs or replacement.
Our editorial standard prioritises relevant manufacturer documentation and official regulatory sources. The sources and verification status for a record should be checked alongside the data.
A statement is not verified merely because a source is listed. Where supporting evidence is missing or conflicting, the record should identify that limitation. Please report unsupported or inconsistent information.
Transparency in gaps
A missing or unverified value does not mean the manufacturer has withheld it. We distinguish information not yet verified, information not available to us, and information explicitly not disclosed by the source.
Regulatory Stability
EU regulations are referenced using CELEX identifiers for long-term stability.
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
Type-approval guidance and documentation.
Records are subject to review and correction. Source links, dates and verification notes should be read with the technical information. Our Editorial and Sourcing Policy explains our standards and review process.
Found an error or missing source? Report a problem with this page. Include the field or statement concerned and a supporting source if available. You can also email corrections@enginecode.uk.
Copyright and permissions
Images and other material may be protected by copyright. Attribution does not by itself grant permission to reuse material. If you believe material on this site infringes your rights, contact copyrights@enginecode.uk with the page URL and details of your claim. We will review the material and take appropriate action.
Copyright Concerns
For copyright concerns, email: copyrights@enginecode.uk
Our Privacy Policy explains how Engine Finders UK Ltd uses information from visits, vehicle lookups, enquiries and messages. Our Cookie Policy explains cookies and similar technologies and how to change your choices.
For access, correction, or deletion requests, email: gdpr@enginecode.uk
Trademark Notice
All trademarks, logos, and engine codes are the property of their respective owners. Use on this site is strictly for reference and identification.
Ownership and commercial services
EngineCode.uk is owned and operated by Engine Finders UK Ltd. Alongside our reference content, we offer an optional replacement-engine enquiry service through Engine Finders and may identify relevant services provided by businesses connected with us. These commercial connections are disclosed. Using an enquiry service is not required to read our reference content.
Engine Finders UK Ltd operates this website. Our optional enquiry service has a commercial purpose. Our Ownership and Commercial Disclosure explains the relationship between the reference website and that service. Participating suppliers pay a fee or subscription to participate on the network and receive quote requests.
Use this record as a starting point for identification. Specifications and vehicle applications may contain errors or omissions. Confirm the exact engine variant and compatibility using vehicle-specific documentation and a qualified supplier or technician.
All external links open in new tabs. Please verify current availability of resources.