The Mercedes — Benz M104.945 is a 3,199 cc, inline — six petrol engine produced between 1993 and 1998. It belongs to the M104 series, engineered for refined performance and durability in mid — to — large luxury sedans and coupes. Featuring a dual overhead camshaft (DOHC), four — valves — per — cylinder design, and Bosch KE — Jetronic continuous fuel injection, it delivered 140 kW (190 PS) and 270 Nm of torque, offering smooth power delivery and strong mid — range responsiveness.…
All M104.945 engines meet Euro 2 emissions standards . No Euro 3 variants were produced.
The Mercedes-Benz M104.945 is a 3,199 cc inline-six petrol engine engineered for executive sedans and coupes (1993–1998). It combines DOHC valvetrain architecture with Bosch KE-Jetronic continuous fuel injection to deliver smooth power delivery and long-term reliability. Designed to meet Euro 2 emissions standards, it balances refinement with durability.
| Parameter | Value | Source |
|---|---|---|
Displacement | 3,199 cc | |
Fuel type | Petrol | |
Configuration | Inline-6, DOHC, 24-valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 87.0 mm × 88.5 mm | |
Power output | 140 kW (190 PS) @ 5,500 rpm | |
Torque | 270 Nm @ 4,000 rpm | |
Fuel system | Bosch KE-Jetronic (mechanical-electronic continuous injection) | |
Emissions standard | Euro 2 | |
Compression ratio | 10.0:1 | |
Cooling system | Water-cooled | |
Turbocharger | N/A | |
Timing system | Single-row timing chain (interference design) | |
Oil type | Refer to vehicle handbook / manufacturer specification | |
Dry weight | 195 kg |
The Mercedes-Benz M104.945 was used across Mercedes-Benz's W124/C124 platforms with longitudinal mounting and no licensing partnerships. This engine received platform-specific adaptations-longer intake runners in the W124 and revised exhaust manifolds in the C124-and from 1996 the facelifted W124 adopted updated emissions controls, creating interchange limits. All adaptations are documented in OEM technical bulletins.
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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.
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The M104.945 is generally robust and durable, but early models (1993-1996) are prone to camshaft wear if maintenance is neglected. Later revisions (post-1996) feature improved intake manifolds and ignition components, enhancing longevity. Regular oil changes with correct specification (10W-40 MB 229.1) and inspection of fuel and vacuum systems ensure reliable operation over 200,000 km.
Key issues include camshaft lobe wear (especially pre-1996), KE-Jetronic fuel distributor faults, vacuum leaks from intake boots, and oil seepage from valve cover gaskets. These are well-documented in Mercedes technical bulletins. Fuel system cleanliness and consistent lubrication are critical to preventing major failures.
This 3.2L inline-six was used in several mid-range models: W124 E-Class (320E, 320TE), C124 C-Class (320CE), and C126 SEC (320SEC). Production spanned 1993 to 1998, all meeting Euro 2 compliance. It was not licensed to other manufacturers.
Limited tuning potential exists due to its naturally aspirated DOHC design. Performance gains are modest and typically involve exhaust upgrades, intake modifications, and fuel distributor recalibration. Some enthusiasts install M104.991 cylinder heads for better breathing. However, stock configuration prioritizes smoothness over high output.
Moderate by modern standards. In a W124 320E, typical consumption is ~13.5 L/100km (city) and ~8.8 L/100km (highway), or about 21 mpg UK combined. Real-world figures depend on driving style and vehicle condition. Expect 19-23 mpg (UK) on mixed roads for a well-maintained example.
Yes. The M104 series is an interference engine. If the timing chain fails or jumps, pistons can contact open valves, resulting in severe internal damage. Chain inspection and tensioner function are critical, especially on high-mileage engines. Any unusual noise from the front of the engine should be investigated immediately.
Mercedes specifies SAE 10W-40 oil meeting MB 229.1 specification. Use a high-quality mineral or semi-synthetic oil designed for older petrol engines. Change intervals should not exceed 10,000 km or annually to ensure proper cam lobe lubrication and prevent wear in high-load areas.
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DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
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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.
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