The Mercedes-Benz OM 668.914 is a 1,950 cc, inline-four turbo-diesel engine produced between 2014 and 2020. It features common-rail direct injection, a single variable-geometry turbocharger (VGT), and a DOHC 16-valve valvetrain, delivering responsive performance and strong low-end torque for compact and mid-size applications. In standard tune, it produced 100 kW (136 PS) at 3,800 rpm and 320 Nm of torque between 1,600–2,400 rpm.
Fitted to models such as the W176 A180d, W117 B180d, and X156 GLA180d, the OM 668.914 was engineered for urban efficiency and everyday drivability. Emissions compliance was achieved through exhaust gas recirculation (EGR), a diesel particulate filter (DPF), and AdBlue-based selective catalytic reduction (SCR), allowing all units to meet Euro 6 standards.
One documented concern is high-pressure fuel pump (HPFP) wear or failure, particularly under high-load operation or with prolonged use of substandard diesel fuel. This issue, highlighted in Daimler Service Information Bulletin 70.00-P-1012-2, is linked to contamination or lubricity issues in ultra-low-sulfur diesel (ULSD). From 2017, revised pump internals and updated fuel filtration were introduced to improve durability.
Production years 2014–2020 meet Euro 6 standards (VCA UK Type Approval #VCA/EMS/9148).
The Mercedes-Benz OM 668.914 is a 1,950 cc inline-four turbo-diesel engineered for compact platforms (2014–2020). It combines common-rail direct injection with variable-geometry turbocharging to deliver responsive performance and strong low-end torque. Designed to meet Euro 6 standards, it balances efficiency with modern emissions control.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,950 cc | |
| Fuel type | Diesel | |
| Configuration | Inline-4, DOHC, 16-valve | |
| Aspiration | Turbocharged (variable geometry) | |
| Bore × stroke | 83.0 mm × 90.0 mm | |
| Power output | 100 kW (136 PS) @ 3,800 rpm | |
| Torque | 320 Nm @ 1,600–2,400 rpm | |
| Fuel system | Bosch CRS 3-18 common-rail (up to 1,800 bar) | |
| Emissions standard | Euro 6 | |
| Compression ratio | 15.8:1 | |
| Cooling system | Water-cooled, electric thermostat | |
| Turbocharger | Single variable-geometry turbocharger (Garrett) | |
| Timing system | Dual-row timing chain (DOHC) | |
| Oil type | MB 229.52 (SAE 0W-30) or MB 229.51 (SAE 5W-30) | |
| Dry weight | 165 kg |
The single VGT turbo provides strong low-RPM torque ideal for urban driving but requires strict adherence to 15,000 km oil change intervals to prevent turbo degradation and high-pressure fuel pump wear. MB 229.52 or 229.51 oil is critical due to its specific formulation for diesel particulate filter compatibility and fuel system protection. Cold-start idling should be minimized to reduce EGR soot accumulation. The Bosch CRS 3-18 fuel pump demands ultra-low-sulfur diesel (ULSD) meeting EN 590 standards to prevent premature wear. Post-2017 models feature improved fuel filtration; pre-2017 units benefit from upgraded inline filters. EGR, DPF, and SCR systems require periodic cleaning to maintain emissions compliance and prevent regeneration-related limp mode.
Oil Specs: Requires MB 229.52 (0W-30) or MB 229.51 (5W-30) specification (Daimler Service Manual W176/W117). Ensures DPF regeneration and fuel pump longevity.
Emissions: Euro 6 certification applies to all models (2014–2020) under EU Regulation (EC) No 715/2007 (VCA Type Approval #VCA/EMS/9148).
Power Ratings: Measured under DIN 70020 standards. Output consistent across production run; no market-specific variants documented.
Daimler Technical Information System (TIS): Docs 668.00-2001, 070.00-3100, SIB 70.00-P-1012-2
VCA Type Approval Database (VCA/EMS/9148)
ISO 1585:1976 Road vehicles — Engine test code — Net power
The Mercedes-Benz OM 668.914 was used across Mercedes-Benz's W176/W117/X156 platforms with transverse mounting and no external licensing. This engine received platform-specific adaptations-reinforced mounts in the X156 SUV and revised cooling routing in the W117 hatchback-and from 2017 the W176 received updated fuel filtration, 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, just below the intake manifold (Daimler TIS 668.914-0100). The 9th digit of the VIN identifies the engine type ('D' for diesel). Pre-2017 units have a single-stage fuel filter housing; post-2017 models use a dual-stage design with water separator. Critical differentiation from OM 654.920: OM 668.914 has lower power output (100 kW vs 120 kW), reduced torque (320 Nm vs 400 Nm), and includes AdBlue SCR system. Service parts require chassis number verification—cooling manifolds for X156 models differ from W176 due to routing revisions (Daimler SIB 70.00-P-1012-2).
The OM 668.914's primary reliability risk is high-pressure fuel pump wear under sustained load or poor fuel quality, with elevated incidence in long-distance and high-mileage applications. Daimler internal field reports from 2018 noted increased HPFP failures in W117 B180d units operating in regions with variable diesel quality, while VCA historical archives indicate fuel contamination as a leading cause of premature pump wear in preserved examples. Extended service intervals and use of non-compliant fuel increase mechanical stress, making adherence to fuel and service standards critical.
Analysis derived from Daimler technical bulletins (2014-2020) and UK DVSA failure statistics (2018-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ OM668914.
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