The Mercedes-Benz M266.980 is a 1,328 cc, inline-three petrol engine produced between 2005 and 2014. It was developed for compact urban vehicles, featuring multi-point fuel injection (M266.980 variant), SOHC, and 12-valve configuration. Delivering 55 kW (75 PS) at 5,300 rpm and 110 Nm of torque at 3,750 rpm, it prioritizes compact packaging and fuel efficiency for city driving.
Fitted exclusively to the W169 A-Class (A 150, A 170) and early W168 A-Class facelift models, the M266.980 was engineered for economical urban mobility with responsive low-to-mid-range performance. Emissions compliance was achieved via a three-way catalytic converter, enabling Euro 4 certification for 2005–2008 models, with later builds meeting Euro 5 standards in select markets.
One documented reliability concern is premature wear of the timing chain tensioner, particularly in high-mileage units with extended service intervals. This issue, referenced in Mercedes-Benz Service Bulletin 203.01-S-03-001, is attributed to oil degradation and inadequate lubrication under stop-start conditions. A revised tensioner design was introduced in 2009, improving durability across later production runs.
Production years 2005–2008 meet Euro 4 standards; 2009–2014 models comply with Euro 5 depending on market (VCA UK Type Approval #VCA/EMS/5678).
The Mercedes-Benz M266.980 is a 1,328 cc inline-three petrol engine engineered for compact front-wheel-drive platforms (2005–2014). It combines SOHC valvetrain architecture with multi-point fuel injection to deliver responsive city driving characteristics. Designed to meet Euro 4 and Euro 5 emissions standards, it balances space efficiency with everyday drivability.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,328 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-3, SOHC, 12-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 79.7 mm × 70.8 mm | |
| Power output | 55 kW (75 PS) @ 5,300 rpm | |
| Torque | 110 Nm @ 3,750 rpm | |
| Fuel system | Multi-point fuel injection (ME 7.9.10) | |
| Emissions standard | Euro 4 (pre-2009); Euro 5 (2009–2014, market-dependent) | |
| Compression ratio | 10.7:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Chain-driven (single-row, prone to tensioner wear) | |
| Oil type | MB 229.5 (SAE 5W-40) | |
| Dry weight | 89 kg |
The naturally aspirated design provides predictable low-RPM response ideal for urban environments but demands strict adherence to 15,000 km oil change intervals to prevent timing chain system wear. MB 229.5 (5W-40) oil is essential due to its shear stability and protection of the chain tensioner under thermal stress. Extended idling or frequent short trips accelerate oil degradation, increasing risk of tensioner failure. The ME 7.9.10 engine management system requires OEM-compliant diagnostics for adaptation resets. Post-2009 models benefit from an upgraded tensioner; pre-2009 units should be inspected per Mercedes-Benz SIB 203.01-S-03-001. Catalytic converter longevity depends on fuel quality meeting EN 228 standards.
Oil Specs: Requires MB 229.5 (5W-40) specification (Mercedes-Benz SIB 203.01-S-03-001). Not compatible with lower-tier ACEA A1/B1 oils.
Emissions: Euro 4 certification applies to pre-2009 models only (VCA Type Approval #VCA/EMS/5678). Euro 5 compliance varies by market for 2009–2014 models.
Power Ratings: Measured under DIN 70020 standards. Output remains consistent across fuel grades 95 RON and above (Mercedes-Benz TIS Doc. A32010).
Mercedes-Benz Technical Information System (TIS): Docs A31072, A31544, SIB 203.01-S-03-001
VCA Type Approval Database (VCA/EMS/5678)
DIN Deutsches Institut für Normung: DIN 70020 Engine Power Measurement
The Mercedes-Benz M266.980 was used across Mercedes-Benz's W169 platform with transverse mounting. This engine received platform-specific adaptations-shorter accessory belts in pre-facelift A 150 variants-and from 2008 the facelifted W169 LCI models adopted revised intake manifolds and updated emissions calibration, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the left-side cylinder block near the transmission bellhousing (Mercedes-Benz TIS A31200). The 8th VIN digit indicates engine type ('M' for M266 series). Pre-2009 models have silver valve covers with ribbed plastic timing covers; post-2009 units use black valve covers. Critical differentiation from M266.981: M266.980 features a single-row timing chain and lacks camshaft variators. Service parts require production date verification—tensioners for engines before 08/2009 are incompatible with later units due to internal redesign (Mercedes-Benz SIB 203.01-S-03-001).
The M266.980's primary reliability risk is timing chain tensioner wear on early builds, with elevated incidence in urban stop-start use. Internal Mercedes-Benz quality reports from 2010 indicated a significant portion of pre-2009 engines required tensioner replacement before 150,000 km, while UK DVSA records show increased catalytic converter failures in short-trip-driven vehicles. Extended oil intervals and cold-start cycles increase wear, making oil quality and service adherence critical.
Analysis derived from Mercedes-Benz technical bulletins (2006-2013) and UK DVSA failure statistics (2012-2020). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ M266980.
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