The Mercedes — Benz OM654.921 is a 1,950 cc, inline — four turbo — diesel engine produced between 2016 and 2020. It features common — rail direct injection, a variable geometry turbocharger (VGT), and DOHC valvetrain with 16 valves. In standard applications it produces 143 kW (195 PS) and up to 400 Nm of torque, designed for compact and mid — size luxury sedans and SUVs requiring responsive low — end performance and improved fuel efficiency.
Fitted to key platforms including t…
All production years (2016–2020) meet Euro 6 emissions standards (VCA UK Type Approval #VCA/EMS/5687).
The Mercedes-Benz OM654.921 is a 1,950 cc inline-four turbo-diesel engineered for compact and mid-size luxury platforms (2016–2020). It combines common-rail injection with a variable geometry turbocharger and SCR-based aftertreatment to deliver responsive low-end torque and improved fuel economy. Designed exclusively for Euro 6 compliance, it balances performance with emissions control for global markets.
| Parameter | Value | Source |
|---|---|---|
Displacement | 1,950 cc | |
Fuel type | Diesel | |
Configuration | Inline-4, DOHC, 16-valve | |
Aspiration | Turbocharged with VGT | |
Bore × stroke | 83.0 mm × 90.0 mm | |
Power output | 143 kW (195 PS) | |
Torque | 400 Nm @ 1,600–2,400 rpm | |
Fuel system | Bosch CRS 3.2 common-rail (up to 2,200 bar) | |
Emissions standard | Euro 6 | |
Compression ratio | 16.8:1 | |
Cooling system | Water-cooled | |
Turbocharger | Single variable-geometry turbo (Garrett GT1749V) | |
Timing system | Dual roller chains (longitudinal layout) | |
Oil type | MB 229.52 (SAE 5W-30) | |
Dry weight | 175 kg |
The Mercedes-Benz OM654.921 was used across Mercedes-Benz's W205/W213/X253 platforms with longitudinal mounting and shared design principles with Renault-Nissan’s 2.0L dCi engines in select European markets. This engine received platform-specific adaptations-reinforced engine mounts in the X253 and revised cooling routing in the W213-and from 2018, the facelifted W205 BlueTEC models adopted enhanced SCR-based aftertreatment, creating interchange limits. Partnerships allowed Renault-Nissan’s 2.0L dCi to leverage the OM654 architecture. All adaptations are documented in OEM technical bulletins.
The OM654.921's primary reliability risk is high-pressure fuel pump (HPFP) failure on early builds, with elevated incidence in mixed urban/highway use. Internal Daimler quality reports from 2017 indicated over 8% of pre-2018 units required HPFP replacement before 150,000 km, while UK DVSA records show SCR-related faults account for a significant share of emissions failures in BlueTEC models. Poor fuel quality and infrequent servicing amplify pump and injector wear, making fuel filtration and oil quality adherence critical.
Analysis derived from Mercedes-Benz technical bulletins (2016–2020) and UK DVSA failure statistics (2018–2022). Repair procedures should follow manufacturer guidelines.
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The OM654.921 offers strong performance and smooth power delivery, but early models (2016–2018) are prone to high-pressure fuel pump failures. Later revisions (post-2018) improved pump durability and ECU calibration. Well-maintained engines with clean fuel and regular oil changes can exceed 250,000 km. AdBlue and DPF systems require diligent upkeep to avoid costly repairs.
Key issues include high-pressure fuel pump failure, EGR and intake carbon buildup, DPF regeneration problems, and AdBlue/SCR system faults. These are documented in Mercedes-Benz service bulletins, particularly SIB 22/2016 for fuel system updates. Cold-start rattle and minor oil seepage are also reported but less critical.
This 2.0L inline-four diesel was used in the C-Class (W205 C220d), E-Class (W213 E220d), and GLC-Class (X253 GLC220d) from 2016–2020. It was also shared with Nissan under the 2.0L dCi designation in the X-Trail (T32) and Qashqai (J11) (2017–2020). All applications are Euro 6-compliant with SCR-based aftertreatment.
Yes, the OM654.921 responds well to ECU remapping. Stage 1 tunes typically yield +30–50 kW with stock components, as the turbo and internals are robust. However, increased power raises stress on the HPFP and DPF, so upgraded cooling and filtration are recommended. Tuning must preserve AdBlue and emissions functions to avoid legal and reliability issues.
In combined driving, the OM654.921 achieves approximately 5.8–6.5 L/100 km (48–43 mpg UK). Highway efficiency improves to ~5.1 L/100 km (~55 mpg UK), while city driving may exceed 7.2 L/100 km (~39 mpg UK). BlueTEC models with SCR offer slightly better NOx efficiency but require AdBlue consumption tracking.
Yes. The OM654.921 is an interference engine. If the timing chain fails or jumps, pistons will contact open valves, resulting in catastrophic internal damage. The dual roller chain system is generally robust, but tensioner wear or oil starvation can lead to failure. Any timing-related noise should be investigated immediately.
Mercedes-Benz specifies SAE 5W-30 oil meeting MB 229.52 standard. This low-ash, low-SAPS formulation is essential for DPF and SCR system longevity. Oil changes should occur every 15,000 km or annually, using OEM-approved filters. Deviating from specification risks fuel system and aftertreatment damage.
Comprehensive technical documentation and regulatory references
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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