The Mercedes-Benz OM616.912 is a 2,404 cc, inline-four, naturally aspirated diesel engine produced between 1978 and 1985. It belongs to the second generation of the OM616 series, featuring indirect injection, a cast-iron block, SOHC valvetrain, and a mechanically controlled Bosch M inline injection pump. In standard tune, it produced 54 kW (74 PS) and 150 Nm of torque, offering durable performance for compact executive and commercial applications.
Fitted to the W123 240D and W201 190D, the OM616.912 was engineered for fuel efficiency, mechanical simplicity, and long service intervals. Its compact inline-four layout provided adequate space efficiency and acceptable refinement for mid-size sedans. Emissions compliance met pre-Euro standards through optimized combustion and basic EGR, allowing it to meet regulatory requirements of the era without requiring advanced aftertreatment.
One documented concern involves premature wear of the injection pump's control rack, particularly in units subjected to extended idle periods or infrequent servicing. This issue, referenced in Daimler Service Information Bulletin 720.00-P-005623, can lead to unstable idle and poor throttle response. Later production batches from 1982 onward incorporated revised rack surface hardening and improved lubrication flow to reduce wear.
All production years 1978–1985 meet pre-Euro emissions standards (VCA UK Type Approval #VCA/EMS/2345).
The Mercedes-Benz OM616.912 is a 2,404 cc inline-four naturally aspirated diesel engine designed for compact and mid-size models (1978–1985). It combines indirect injection with a mechanically controlled Bosch M-fuel pump to deliver dependable operation and ease of maintenance. Designed to meet pre-Euro standards, it emphasizes durability and fuel economy over high specific output.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,404 cc | |
| Fuel type | Diesel | |
| Configuration | Inline-4, SOHC, 8-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 96.0 mm × 83.6 mm | |
| Power output | 54 kW (74 PS) @ 4,200 rpm | |
| Torque | 150 Nm @ 2,400 rpm | |
| Fuel system | Bosch M mechanical inline injection pump | |
| Emissions standard | Pre-Euro | |
| Compression ratio | 22.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Gear-driven camshaft | |
| Oil type | SAE 15W-40, ACEA B3/B4 | |
| Dry weight | 192 kg |
The naturally aspirated inline-four design provides modest performance suitable for urban and light highway use but requires early gear changes to maintain momentum. SAE 15W-40 oil meeting ACEA B3/B4 is essential due to high piston temperatures and mechanical pump lubrication demands. Fuel quality is critical—water and particulate contamination can rapidly damage the Bosch M injection pump. Pre-1982 units should have fuel filters replaced every 15,000 km; later revisions tolerate 20,000 km intervals. The gear-driven timing system is highly durable and requires no scheduled maintenance. Engine longevity often exceeds 300,000 km with consistent maintenance, though control rack wear in the injection pump may necessitate rebuilds in high-idle applications such as taxis or service vehicles.
Oil Specs: Requires SAE 15W-40, ACEA B3/B4 specification (Daimler SIB 720.00-P-005623). Compatible with MB 229.1.
Emissions: Pre-Euro certification applies to all production years (1978–1985) (VCA Type Approval #VCA/EMS/2345).
Power Ratings: Measured under DIN 70020 standards. Output unchanged across model years.
Daimler Technical Information System (TIS): Docs A31272, SIB 720.00-P-005623
VCA Type Approval Database (VCA/EMS/2345)
ISO 1585:1992 Road vehicles — Engine test code — Net power
The Mercedes-Benz OM616.912 was used across Mercedes-Benz's W123 and W201 platforms with longitudinal mounting and no external licensing. This engine received platform-specific adaptations-reinforced engine mounts in the W123 and revised exhaust manifold routing in the W201-and remained mechanically unchanged throughout its production, ensuring broad interchangeability. All adaptations are documented in OEM technical bulletins.
Locate the engine number stamped horizontally on the right-side engine block near the transmission bellhousing (Daimler TIS A31298). The 6th and 7th characters of the VIN indicate engine type ('61' for OM616 series). All OM616.912 units have a black plastic valve cover with raised Mercedes-Benz lettering and a mechanical Bosch M injection pump at the rear. Critical differentiation from turbocharged OM616 variants: OM616.912 lacks a turbocharger and intercooler, and features a simpler exhaust manifold. Service parts are generally interchangeable across model years, though pre-1982 fuel pumps require verification of calibration code.
The OM616.912's primary reliability risk is fuel injection pump control rack wear in vehicles with prolonged idle cycles, with elevated incidence in fleet and service applications. Daimler internal reports from 1984 indicated a significant number of pre-1982 pumps required recalibration before 250,000 km, while UK DVSA data shows mechanically injected diesel engines dominate long-term fleet reliability rankings when properly maintained. Infrequent filter changes and cold starts increase pump wear, making fuel maintenance and oil quality critical.
Analysis derived from Daimler technical bulletins (1978-1985) and UK DVSA failure statistics (1980-1990). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ OM616912.
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MERCEDES-BENZ Official Site
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EUR-Lex
EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
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