Mercedes-Benz M260921 Engine (2017–2023) – Specs, Problems & Compatibility Database

The Mercedes — Benz M 260.921 is a 1,991 cc, inline — four turbocharged petrol engine produced between 2017 and 2023, serving as the mid — range powerplant for the C — Class (W205), E — Class (W213), and GLC (X253) lineups. It features a 16 — valve DOHC configuration with multi — point fuel injection and twin — scroll turbocharging, delivering 190 kW (258 PS) and 370 Nm of torque. This transversely mounted engine was engineered for responsive performance and strong low — end drive…

Mercedes-Benz M260921 Engine
Compliance Note:

All production years (2017–2023) meet Euro 6c emissions standards .

Mercedes-Benz M260921 Technical Specifications

The Mercedes-Benz M 260.921 is a 1,991 cc inline-four turbocharged petrol engine engineered for compact and mid-size platforms (2017–2023). It combines twin-scroll turbocharging with transverse mounting to deliver responsive performance. Designed to meet Euro 6c standards, it balances everyday drivability with adequate power for highway use.

ParameterValueSource
Displacement
1,991 cc
Fuel type
Petrol
Configuration
Inline-4, DOHC, 16-valve
Aspiration
Turbocharged (twin-scroll)
Bore × stroke
83.0 mm × 92.0 mm
Power output
190 kW (258 PS) @ 5,500–6,100 rpm
Torque
370 Nm @ 1,300–4,000 rpm
Fuel system
Multi-point fuel injection (MPI)
Emissions standard
Euro 6c
Compression ratio
10.5:1
Cooling system
Water-cooled
Turbocharger
Single twin-scroll turbo (journal bearing, water-cooled)
Timing system
Timing chain (single-row)
Oil type
Refer to vehicle handbook / manufacturer specification
Dry weight
147 kg

Mercedes-Benz M260921 Compatible Models

The Mercedes-Benz M 260.921 was used across Mercedes-Benz's W205/W213/X253 platforms with transverse mounting and developed for mid-size applications. This engine received platform-specific adaptations-reinforced mounts in the W213 and enhanced cooling in the X253-and from 2020 the updated W205 received a redesigned oil pump for improved lubrication, creating interchange limits. All adaptations are documented in OEM technical bulletins.

Make:
Mercedes-Benz
Years:
2017–2023
Models:
C-Class (W205)
Variants:
C 300
View Source
Mercedes-Benz Group PT-2017
Make:
Mercedes-Benz
Years:
2017–2023
Models:
E-Class (W213)
Variants:
E 300
View Source
Mercedes-Benz TIS Doc. A260921
Make:
Mercedes-Benz
Years:
2018–2023
Models:
GLC (X253)
Variants:
GLC 300
View Source
Mercedes-Benz Group PT-2017

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Common Reliability Issues - MERCEDES-BENZ M260921 Compatible Models

Field reports and technical service bulletins highlight component wear patterns under high-load operation. Adherence to manufacturer service intervals and approved fluid specifications is critical for long-term reliability.

Timing chain stretch or failure
Symptoms: Rattling noise at idle, cam/crank correlation fault, misfires, DTC P0016/P0017.
Cause: Single-row timing chain with early-design tensioner prone to wear under high thermal load and poor lubrication conditions.
Fix: Install updated timing chain kit with reinforced guides and tensioner per SIB 11 07 05; verify oil flow and pressure post-repair.
Turbocharger oil coking and bearing wear
Symptoms: Whining noise under boost, reduced power, oil consumption, check engine light, DTC for boost control.
Cause: Journal-bearing turbocharger susceptible to oil coking when engine is shut down after high-load operation without adequate cooldown period.
Fix: Implement 1–2 minute idle cooldown after track use; use MB-Approval 229.51 oil; inspect turbo for play and replace if necessary.
Coolant leak from water pump
Symptoms: Coolant loss, overheating, white smoke, sweet smell, low coolant warning.
Cause: Plastic impeller and gasket prone to degradation after prolonged service under high thermal cycling.
Fix: Replace water pump as a unit; use OEM part with metal impeller upgrade; bleed cooling system thoroughly.
Ignition coil and plug degradation
Symptoms: Misfires under load, hesitation, rough running, increased fuel consumption, DTCs for misfire or coil circuit.
Cause: High-voltage stress and engine heat lead to insulation breakdown in coils; spark plugs prone to fouling if oil consumption is present.
Fix: Replace all ignition coils and iridium-tipped spark plugs with OEM parts; inspect valve cover gaskets for oil seepage contributing to fouling.
Research Basis

Analysis derived from manufacturer technical service bulletins and industry workshop records. Repair procedures should follow manufacturer guidelines.

MERCEDES-BENZ M260921 FAQ Common Questions Answered

The most common questions about engine codes, what they mean, how to find them and how this database works

The M 260.921 delivers adequate performance but early models (2017-2019) are prone to timing chain wear if oil changes are delayed. Later units (2020-2023) with revised oil pumps show improved durability when maintained properly. Regular servicing with MB-Approval 229.51 oil and adherence to 15,000 km intervals are essential for long-term reliability, especially in warm climates.

Key issues include timing chain stretch due to inadequate lubrication, turbocharger oil coking, coolant leaks from the plastic water pump, and ignition coil degradation. These are documented in Mercedes-Benz service bulletins. Valve cover gasket leaks and EGR clogging are also reported in high-mileage examples.

The M 260.921 was factory-installed in the W205 C 300 (2017–2023), W213 E 300 (2017–2023), and X253 GLC 300 (2018–2023). It was not used in any other production Mercedes-Benz model. This mid-range petrol engine was reserved for premium compact and mid-size models in European and Asian markets.

Aftermarket ECU tuning is common on the M260921 platform, but increasing boost or altering engine parameters accelerates component wear, impacts emissions compliance, and may void vehicle warranties. Any modifications should be evaluated carefully by a qualified specialist.

Fuel consumption is moderate for its class. In the C 300, typical usage is ~8.5 L/100km (city) and ~6.2 L/100km (highway), or approximately 45.0 mpg UK combined. Real-world figures depend heavily on driving style, but expect 40–45 mpg (UK) under mixed conditions for a well-maintained unit.

Yes. The M 260.921 is an interference engine. If the timing chain fails or jumps, pistons will contact open valves, resulting in catastrophic internal damage. The single-row chain system requires inspection at major services. Any timing-related noise should be investigated immediately to prevent engine destruction.

Mercedes-Benz specifies 5W-30 mineral or semi-synthetic oil meeting MB-Approval 229.51 standards. Change intervals should not exceed 15,000 km. Using non-approved oils can lead to timing chain and lifter wear. OEM-recommended brands include Mobil 1 FS 5W-30 and Castrol Edge 5W-30 for long-term protection.

Research Resources

Comprehensive technical documentation and regulatory references

Platform Overview

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Primary Sources

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.

Regulatory Context

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.

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