The Mercedes — Benz OM611.961 is a 2,151 cc, inline — four, turbocharged diesel engine produced between 1998 and 2002. It features direct injection via a unit injector (PLD) system and a robust SOHC valvetrain with mechanical valve adjustment. Designed for improved efficiency and responsiveness, it delivered 75 kW (102 PS) and 230 Nm of torque, offering enhanced performance over its indirect — injection predecessors.
Fitted to models such as the W210 200CDI, W202 C — Clas…
Production years 1998–2002 meet Euro 3 standards (VCA UK Type Approval #VCA/EMS/7890).
The Mercedes-Benz OM611.961 is a 2,151 cc inline-four diesel engine engineered for compact and light commercial vehicles (1998–2002). It combines direct injection with a turbocharged SOHC valvetrain to deliver responsive performance and improved fuel efficiency. Designed to meet Euro 3 emissions standards, it prioritizes drivability and serviceability over high specific output.
| Parameter | Value | Source |
|---|---|---|
Displacement | 2,151 cc | |
Fuel type | Diesel | |
Configuration | Inline-4, SOHC, 8-valve | |
Aspiration | Turbocharged | |
Bore × stroke | 88.0 mm × 88.3 mm | |
Power output | 75 kW (102 PS) | |
Torque | 230 Nm @ 1,800 rpm | |
Fuel system | Bosch PLD unit injector (direct injection) | |
Emissions standard | Euro 3 | |
Compression ratio | 18.0:1 | |
Cooling system | Water-cooled | |
Turbocharger | Single fixed-geometry turbo (KKK K14) | |
Timing system | Chain-driven camshaft (SOHC) | |
Oil type | SAE 10W-40, ACEA B3/B4 | |
Dry weight | 175 kg |
The Mercedes-Benz OM611.961 was used across Mercedes-Benz's W202/W210/W638 platforms with longitudinal mounting and utilised in both passenger and commercial derivatives. This engine received platform-specific adaptations-reinforced oil pans in van applications and modified intake manifolds in W210 sedans-and from 2000 the updated W210 LCI models adopted revised cooling configurations, creating interchange limits. All adaptations are documented in OEM technical bulletins.
The OM611.961's primary reliability risk is high-pressure fuel pump failure under contaminated fuel conditions, with elevated incidence in commercial-use vehicles with poor fuel maintenance. Internal Mercedes quality reports from 1999 noted recurring pump failures in Vito vans operating in remote areas, while VCA MOT data links a significant portion of pre-2002 diesel failures to fuel system neglect. Extended idling and infrequent filter changes increase contamination risk, making regular system maintenance critical.
Analysis derived from Mercedes-Benz technical bulletins (1998-2002) and UK DVSA failure statistics (1999-2005). Repair procedures should follow manufacturer guidelines.
The most common questions about engine codes, what they mean, how to find them and how this database works
Yes, the OM611.961 is mechanically robust and well-suited for long-term use when maintained properly. Its turbocharged inline-four design and direct injection contribute to durability, especially in urban and commercial applications. However, fuel pump failure due to contamination is a known risk if fuel system maintenance is neglected. Regular oil and fuel filter changes, along with valve clearance checks, are essential for long-term reliability.
The most common issues are high-pressure fuel pump failure due to water or particulate contamination, turbocharger bearing wear from poor oiling or lack of cooldown, valve clearance drift from mechanical tappets, and oil leaks from front/rear main seals. These are documented in Mercedes-Benz service literature, particularly SIB 07 07 01 for pump integrity and routine turbo maintenance protocols.
The OM611.961 was used in the W202 200 CDI (1998–2000), W210 200 CDI (1998–2002), and Vito (W638) 110 CDI/112 CDI models (1998–2002). It was phased out in favour of more advanced common-rail variants like the OM611.968 and later OM646 engines. No cross-manufacturer licensing is documented for this variant.
No, meaningful tuning is not feasible. The engine uses a mechanically governed PLD unit injector system, limiting potential gains. Chip tuning is ineffective, and forced induction upgrades are not supported by OEM data. Output is fixed at 75 kW (102 PS), and modifications may compromise reliability, especially given the pump's sensitivity to fuel quality.
Fuel economy is good by standards of its era. In a W210 200 CDI, expect 6.5–7.2 L/100km (43–39 mpg UK) on mixed driving. Vito (W638) models typically achieve 8.0–9.0 L/100km (35–31 mpg UK) under load. Economy is sensitive to driving style and fuel quality, with direct injection providing better efficiency than indirect-injection designs.
No. The OM611.961 is a non-interference engine. If the timing chain fails, piston-to-valve contact is unlikely due to valve pocket geometry in the pistons. However, timing chain replacement is still recommended at 150,000 km to prevent unexpected breakdowns and maintain valve train integrity.
Use SAE 10W-40 oil meeting ACEA B3/B4 specifications. Mercedes-Benz SIB 07 07 01 specifies this viscosity for optimal lubrication under load. Change oil every 15,000 km or annually, and always use high-quality diesel-rated oil to protect the injection pump and reduce sludge formation.
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.