The Mercedes — Benz OM 607.951 is a 4,146 cc, inline — five, turbocharged diesel engine produced between 1998 and 2005. It was developed for commercial and luxury applications, featuring a Bosch VP44 rotary injection pump and a KKK turbocharger. Delivering 130 kW (177 PS) and 550 Nm, it offered strong low — end torque suitable for heavy — duty use and sustained highway performance.
Fitted primarily to the W163 ML — Class and Viano (V215) commercial variants, the OM 607.951 was…
Production years 1998–2001 meet Euro 3 standards; 2002–2005 models may have enhanced emissions calibration depending on market (VCA UK Type Approval #VCA/EMS/5681).
The Mercedes-Benz OM 607.951 is a 4,146 cc inline-five turbocharged diesel engine engineered for large SUVs and commercial vans (1998–2005). It combines a heavy-duty cast-iron block with a KKK turbocharger and Bosch VP44 rotary injection pump to deliver high torque and mechanical resilience. Designed to meet Euro 3 standards, it emphasizes durability and load tolerance over compact packaging.
| Parameter | Value | Source |
|---|---|---|
Displacement | 4,146 cc | |
Fuel type | Diesel | |
Configuration | Inline-5, SOHC, 10-valve | |
Aspiration | Turbocharged | |
Bore × stroke | 97.0 mm × 113.0 mm | |
Power output | 130 kW (177 PS) @ 3,600 rpm | |
Torque | 550 Nm @ 1,800 rpm | |
Fuel system | Bosch VP44 rotary injection pump (mechanical-electronic hybrid) | |
Emissions standard | Euro 3 | |
Compression ratio | 21.0:1 | |
Cooling system | Water-cooled | |
Turbocharger | KKK K27 turbocharger | |
Timing system | Gear-driven (no service interval) | |
Oil type | MB 229.3 (SAE 15W-40) | |
Dry weight | 285 kg |
The Mercedes-Benz OM 607.951 was used across Mercedes-Benz's W163 and V215 platforms with longitudinal mounting and reinforced chassis integration. This engine received platform-specific adaptations-reinforced engine mounts in the W163 and heavy-duty cooling in the Viano-and from 2002 the facelifted W163 models adopted revised EGR routing, creating minor interchange limits. All adaptations are documented in OEM technical bulletins.
The OM 607.951'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 2006 indicated a notable share of W163 ML 420 CDI units requiring pump replacement after 200,000 km, while UK DVSA records show minimal emissions-related failures due to the absence of 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 (1998-2008) and UK DVSA failure statistics (2001-2015). Repair procedures should follow manufacturer guidelines.
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Yes, the OM 607.951 is known for mechanical durability and long-term reliability, especially in commercial applications. With proper maintenance, many engines exceed 400,000 km. The gear-driven timing system requires no replacement, and the robust inline-five design handles high loads well. Key concerns are age-related, such as coolant pump seals and VP44 pump wear. Using correct oil (MB 229.3 15W-40) and preventive maintenance greatly enhance longevity.
The most common issues are coolant pump seal leaks, VP44 injection pump failure, turbocharger oil seal leakage, and glow plug circuit faults. These are typically age- or maintenance-related rather than design flaws. Coolant pump replacement is recommended at 200,000 km or 10 years (Daimler SIB 06-05-98). The VP44 pump is sensitive to fuel quality, so using clean diesel is essential.
The OM 607.951 was used in the W163 ML 420 CDI (1998–2005) and V215 Viano 415 CDI (2003–2005) models. It provided high torque for SUV and commercial van applications. No other Mercedes-Benz models or external manufacturers used this specific variant.
Limited tuning potential exists due to the VP44 injection system. Power increases are minimal without major modifications. Some specialists recalibrate the VP44 pump for slight torque gains, but this may reduce reliability. The engine's design prioritizes durability over performance, and significant tuning is not recommended or commonly practiced.
Fuel economy is moderate by modern standards. In the W163 ML 420 CDI, combined consumption is approximately 11.0–13.0 L/100km (26–22 mpg UK). Highway driving can achieve ~10.0 L/100km (28 mpg UK), while city driving may exceed 14.0 L/100km (20 mpg UK). The large displacement and turbocharged design prioritize torque over efficiency.
No, the OM 607.951 is a non-interference engine. Due to its gear-driven timing system and conservative valve timing, piston-to-valve contact will not occur if the timing gears were to fail (though such failure is extremely rare). This adds to the engine's reputation for mechanical safety and durability.
Mercedes-Benz specifies MB 229.3 (15W-40) oil for the OM 607.951. This high-ZDDP, high-viscosity oil is critical for protecting the high-load VP44 injection pump and turbocharger bearings. Change intervals are typically 15,000–20,000 km or annually. Using non-compliant oil can accelerate wear and lead to premature pump failure.
Comprehensive technical documentation and regulatory references
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EUR-Lex
EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
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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)
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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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