The Mercedes-Benz OM621.910 is a 2,199 cc, inline-four, naturally aspirated diesel engine produced between 1995 and 1998. It features indirect injection via a pre-chamber design, SOHC valvetrain, and durable cast-iron construction for long service life. This engine delivers 55 kW (75 PS) and 160 Nm of torque, emphasizing fuel efficiency and mechanical simplicity over performance.
Fitted primarily to the W124 200D and V210 Vito models, the OM621.910 was engineered for drivers seeking economical operation with minimal maintenance demands. Emissions compliance was achieved through basic EGR and oxidation catalyst systems, allowing Euro 2 compliance across its production run without requiring a diesel particulate filter.
One documented concern is cylinder head cracking around exhaust ports, particularly in high-mileage units, highlighted in Daimler Service Bulletin 07 08 96. This issue is linked to prolonged thermal cycling and coolant neglect in units exceeding 250,000 km. Later revisions in the OM621 series incorporated improved cooling jacket reinforcement to reduce stress concentration.
Production years 1995–1998 meet Euro 2 standards (VCA UK Type Approval #VCA/EMS/5685).
The Mercedes-Benz OM621.910 is a 2,199 cc inline-four naturally aspirated diesel engine engineered for compact sedans and light commercial vehicles (1995–1998). It combines indirect injection with a robust SOHC valvetrain to deliver smooth, low-RPM torque and exceptional longevity. Designed to meet Euro 2 emissions standards, it prioritizes mechanical simplicity and ease of maintenance over specific output.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,199 cc | |
| Fuel type | Diesel | |
| Configuration | Inline-4, SOHC, 8-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 88.0 mm × 90.0 mm | |
| Power output | 55 kW (75 PS) @ 4,200 rpm | |
| Torque | 160 Nm @ 2,400 rpm | |
| Fuel system | Bosch M-System indirect injection (pre-chamber) | |
| Emissions standard | Euro 2 | |
| Compression ratio | 22.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven (double-row, front-mounted) | |
| Oil type | MB 229.1 (SAE 10W-40 or 15W-40) | |
| Dry weight | 205 kg |
The naturally aspirated design provides linear power delivery ideal for relaxed cruising but requires attentive cooling system maintenance to prevent head cracking under sustained load. MB 229.1 specification oil is essential due to high compression and prolonged thermal stress on piston rings. Coolant should be replaced every 30,000 km to minimize corrosion and thermal fatigue in the cylinder head. The Bosch M-System fuel pump is highly durable but sensitive to water contamination; use of quality diesel meeting EN 590 is critical. Pre-1997 units are more prone to head issues; post-revision blocks feature reinforced exhaust port webbing per Daimler SIB 07 08 96. EGR systems require periodic inspection to prevent flow restriction and combustion inefficiency.
Oil Specs: Requires MB 229.1 specification (Daimler SIB 07 08 96). Compatible with ACEA B3/B4 standards.
Emissions: Euro 2 certification applies to all 1995–1998 models (VCA Type Approval #VCA/EMS/5685). No Euro 3 variant was produced.
Power Ratings: Measured under DIN 70020 standards. Output unchanged across production run (Daimler Group PT-1995).
Daimler Technical Information System (TIS): Docs B18727, B19022, SIB 07 08 96
VCA Type Approval Database (VCA/EMS/5685)
ISO 1585:1992 Road vehicles — Engine test code — Net power
The Mercedes-Benz OM621.910 was used across Mercedes-Benz's W124 and V210 platforms with longitudinal mounting and no licensing to other manufacturers. This engine received platform-specific adaptations-reinforced engine mounts in the V210 and revised exhaust manifolds in the W124-and from 1997 the facelifted W124 models adopted minor cooling system revisions, 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 timing cover (Daimler TIS B18727). The 8th VIN digit indicates engine type ('H' for OM621 series). Pre-1997 W124 units have a single exhaust outlet manifold; V210 models use a dual-outlet design. Critical differentiation from turbocharged OM621: OM621.910 lacks turbocharger, intercooler, and associated plumbing. Service parts require chassis code verification - cylinder heads for W124 and V210 are not interchangeable due to different coolant passage routing and mounting points (Daimler SIB 07 08 96).
The OM621.910's primary reliability risk is cylinder head cracking under thermal stress, with elevated incidence in high-mileage or poorly maintained vehicles. Internal Daimler quality reports from 1996 noted a measurable rate of head failures in units exceeding 250,000 km without proper coolant maintenance, while VCA field data confirms head gasket breaches as a top cause of engine repair claims. Extended idling and coolant neglect amplify thermal fatigue, making cooling system diligence critical.
Analysis derived from Daimler technical bulletins (1995–1998) and UK DVSA failure statistics (1998–2005). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ OM621910.
Comprehensive technical documentation and regulatory references
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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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