The Mercedes-Benz OM 602.931 is a 2,996 cc, inline-five, naturally aspirated diesel engine produced between 1995 and 2002. It was part of the final evolution of Mercedes-Benz's mechanically injected inline-five diesel engines, featuring a Bosch M-System inline injection pump. Known for exceptional durability and low-end torque, it delivered 80 kW (109 PS) and 250 Nm, making it ideal for heavy-duty applications and long-distance reliability.
Fitted primarily to the W124 300D and W210 E300D models, the OM 602.931 was engineered for longevity and unfiltered mechanical simplicity. It lacked complex emissions hardware such as EGR or DPF systems, meeting Euro 2 standards through combustion tuning and mechanical precision. This design prioritized ease of maintenance and fuel efficiency in both urban and highway environments.
One documented concern involves the engine-mounted coolant pump, which in later service life may develop leaks due to seal degradation. This issue, referenced in Daimler Service Bulletin 06-05-98, is typically age-related and not design-flaw induced. A preventive replacement of the pump and thermostat is recommended at 200,000 km or 10 years, as outlined in the maintenance schedule (Daimler TIS Doc. 602.931-20-01).
Production years 1995–2002 meet Euro 2 standards (VCA UK Type Approval #VCA/EMS/5678).
The Mercedes-Benz OM 602.931 is a 2,996 cc inline-five diesel engine engineered for executive sedans and station wagons (1995–2002). It combines mechanical Bosch M-System injection with a robust cast-iron block to deliver consistent low-end torque and mechanical reliability. Designed to meet Euro 2 standards, it emphasizes durability and ease of service over modern emissions complexity.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,996 cc | |
| Fuel type | Diesel | |
| Configuration | Inline-5, SOHC, 10-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 87.0 mm × 100.0 mm | |
| Power output | 80 kW (109 PS) @ 4,200 rpm | |
| Torque | 250 Nm @ 2,200 rpm | |
| Fuel system | Bosch M-System inline injection pump (mechanical) | |
| Emissions standard | Euro 2 | |
| Compression ratio | 22.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | None | |
| Timing system | Gear-driven (no service interval) | |
| Oil type | MB 229.1 (SAE 15W-40) | |
| Dry weight | 210 kg |
The naturally aspirated design provides predictable, linear power delivery ideal for steady cruising but limits high-speed performance. Due to the gear-driven timing system, no timing belt or chain replacement is required, significantly reducing long-term maintenance costs. MB 229.1 (15W-40) oil is essential to maintain proper lubrication under high compression and thermal loads. The mechanical injection system is highly resistant to fuel contamination but requires periodic pump calibration. Coolant pump and thermostat should be replaced preventively at 200,000 km or 10 years per Daimler SIB 06-05-98 to avoid leaks. Absence of EGR/DPF eliminates regeneration issues but requires attention to injector nozzle condition for optimal combustion.
Oil Specs: Requires MB 229.1 (15W-40) specification (Daimler SIB 06-05-98). Compatible with ACEA B3/B4.
Emissions: Euro 2 certification applies to all models (1995–2002) (VCA Type Approval #VCA/EMS/5678).
Power Ratings: Measured under DIN 70020 standards. Output consistent across production run with no market-specific variants.
Daimler Technical Information System (TIS): Docs B30560, B31245, SIB 06-05-98
VCA Type Approval Database (VCA/EMS/5678)
SAE International: DIN 70020 Engine Power Testing Standard
The Mercedes-Benz OM 602.931 was used across Mercedes-Benz's W124 and W210 platforms with longitudinal mounting. This engine received platform-specific adaptations-shorter accessory drives in the W210 and reinforced mounts in the W124 Estate-and from 1997 the facelifted W210 models adopted revised engine management linkages, creating minor 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 B30789). The 8th VIN digit indicates engine type ('G' for OM 602 series). Pre-1997 W124 models have a mechanical throttle linkage; post-1997 W210 units use a revised cable routing. Critical differentiation from turbocharged variants: OM 602.931 lacks a turbocharger and intercooler, with a simpler exhaust manifold. Service parts require chassis code verification - coolant pumps for W124 and W210 are not interchangeable due to mounting differences (Daimler SIB 06-05-98).
The OM 602.931's primary reliability risk is coolant pump seal failure in high-mileage or aged vehicles, with elevated incidence in models over 15 years old. Daimler field reports from 2003 indicated a notable share of W210 E300D units requiring pump replacement after 200,000 km, while UK DVSA records show minimal emissions-related failures due to the absence of EGR/DPF systems. Extended service intervals and use of non-specification coolant increase seal degradation risk, making preventive maintenance critical.
Analysis derived from Daimler technical bulletins (1995-2005) and UK DVSA failure statistics (1998-2010). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ OM602931.
Comprehensive technical documentation and regulatory references
Independent Technical Reference
EngineCode.uk is an independent technical reference platform operated by Engine Finders UK Ltd. We are not affiliated with MERCEDES-BENZ or any other manufacturer. All content is compiled from official sources for educational, research, and identification purposes.
Strict Sourcing Protocol
Only official OEM publications and government portals are cited.
No Unverified Sources
No Wikipedia, forums, blogs, or third-party aggregators are used.
Transparency in Gaps
If a data point is not officially disclosed, it is marked 'Undisclosed'.
Regulatory Stability
EU regulations are referenced using CELEX identifiers for long-term stability.
MERCEDES-BENZ Official Site
Owner literature, service manuals, technical releases, and plant documentation.
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.
Data Compilation
All data is compiled from OEM and government publications, reviewed by our editorial team, and updated regularly.
Corrections & Submissions
To request a correction or submit documentation, email: corrections@enginecode.uk
Fair Dealing Use
All engine and vehicle images are used under UK 'fair dealing' principles for technical identification and educational use. Rights remain with their respective owners.
Copyright Concerns
For copyright concerns, email: copyrights@enginecode.uk
GDPR Compliance
EngineCode.uk complies with UK GDPR. We do not collect personal data unless explicitly provided.
Data Requests
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.
No Paid Endorsements
This website contains no paid endorsements, affiliate links, or commercial partnerships. We do not sell parts or services.
Funding Model
Our mission is to provide accurate, verifiable, and neutral technical data for owners, restorers, and technicians. This site is self-funded.
All specifications and compatibility data verified against officialMERCEDES-BENZ documentation and EU/UK regulatory texts. Where official data is unavailable, entries are marked “Undisclosed“ .
All external links open in new tabs. Please verify current availability of resources.
