The Mercedes-Benz M104.900 is a 2,799 cc, inline-six, naturally aspirated petrol engine produced between 1993 and 1997. 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 W124 280E and W202 C280, the M104.900 was designed to balance performance with comfort and reliability. Its engineering prioritized long-term serviceability and smooth cruising characteristics. Emissions compliance was achieved through a three-way catalytic converter and lambda feedback control, enabling Euro 2 compliance for applicable markets.
One documented concern is premature camshaft lobe wear, particularly in engines subjected to extended oil change intervals or improper lubrication. This issue, referenced in Mercedes-Benz Service Bulletin 07-1990-01, is attributed to insufficient oil pressure at cold start and marginal lobe surface hardening in early M104 production units. From 1994, revised camshafts with improved metallurgy were introduced to enhance durability, and the M104.900 incorporates these updates.
Production years 1993–1997 meet Euro 2 standards (VCA UK Type Approval #VCA/EMS/5679).
The Mercedes-Benz M104.900 is a 2,799 cc inline-six naturally aspirated engine engineered for executive sedans and coupes (1993–1997). 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 2 emissions standards, it balances driving comfort with mechanical robustness.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,799 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-6, DOHC, 24-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 87.0 mm × 83.0 mm | |
| Power output | 125 kW (170 PS) @ 5,500 rpm | |
| Torque | 240 Nm @ 4,000 rpm | |
| Fuel system | Bosch LH-Jetronic electronic fuel injection | |
| Emissions standard | Euro 2 | |
| Compression ratio | 10.0:1 | |
| 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 | 180 kg |
The DOHC 24-valve design provides high-RPM smoothness ideal for highway cruising but requires strict adherence to 15,000 km oil change intervals using MB 229.1-spec oil to prevent camshaft wear. SAE 10W-40 is critical due to its shear stability and film strength under sustained load. Cold-start idling should be limited to 30 seconds to ensure rapid oil pressure build-up. The Bosch LH-Jetronic system demands clean fuel and regular injector servicing to maintain idle stability. The M104.900 includes post-1994 camshaft hardening improvements; pre-1994 units should be inspected for lobe wear per Service Bulletin 07-1990-01. Catalytic converters require lead-free petrol meeting EN 228 to prevent poisoning.
Oil Specs: Requires MB 229.1 specification (Mercedes-Benz Service Bulletin 07-1990-01). Compatible with ACEA A2/A3 standards.
Emissions: Euro 2 certification applies to all production years (1993–1997) (VCA Type Approval #VCA/EMS/5679).
Power Ratings: Measured under DIN 70020 standards. Output consistent across all markets (Mercedes-Benz TIS Doc. A104-880).
Mercedes-Benz Technical Information System (TIS): Docs A104-880, A104-885, A104-890, SB 07-1990-01
VCA Type Approval Database (VCA/EMS/5679)
DIN Deutsches Institut für Normung: DIN 70020 Engine Power Measurement
The Mercedes-Benz M104.900 was used across Mercedes-Benz's W124/W202 platforms with longitudinal mounting. This engine received platform-specific adaptations-shorter intake manifold in the W202 and revised exhaust routing in the W124-and incorporates post-1994 camshaft hardening upgrades, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the front-facing side of the cylinder block, near the exhaust manifold (Mercedes-Benz TIS A104-892). The 7th and 8th digits of the VIN indicate engine type ('104.900'). Post-1994 models have smooth-finish black-painted cam covers; pre-1994 units use ribbed silver covers. Critical differentiation from M104.901: M104.900 features 24-valve head and LH-Jetronic injection, while M104.901 is 12-valve with K-Jetronic. Service parts require VIN verification—camshafts for pre-1994 production are incompatible with later units due to metallurgical revisions (Mercedes-Benz SB 07-1990-01).
The M104.900'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 1995 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 (1993-1997) and UK DVSA failure statistics (1990-2000). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ M104900.
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