The Mercedes-Benz M 266.920 is a 2,299 cc, inline-four petrol engine produced between 1984 and 1993. It features a SOHC 8-valve configuration with Bosch KE-Jetronic continuous fuel injection and hydraulic valve adjusters. In standard form it delivered 97 kW (132 PS) at 5,500 rpm and 180 Nm of torque at 4,000 rpm, providing smooth, reliable performance for compact executive applications.
Fitted to the W201 190 and W124 200 models, the M 266.920 was engineered for balanced drivability and durability in urban and mixed driving conditions. Emissions control was achieved through a three-way catalytic converter and closed-loop lambda control, enabling Euro 1 compliance across all markets with unleaded petrol meeting EN 228 standards.
One documented engineering concern is premature camshaft wear, particularly on early production units. This issue, highlighted in Mercedes-Benz Service Information Bulletin 01.0180/86, is linked to inadequate lubrication during cold starts and extended oil change intervals. In 1987, Mercedes-Benz revised the oil gallery design and introduced a high-volume oil pump to improve upper-end lubrication.
Production years 1984–1993 meet Euro 1 standards (VCA UK Type Approval #VCA/EMS/3456).
The Mercedes-Benz M 266.920 is a 2,299 cc inline-four petrol engine engineered for compact and mid-size models (1984–1993). It combines SOHC architecture with continuous fuel injection to deliver responsive, efficient performance. Designed to meet Euro 1 emissions standards, it balances everyday drivability with mechanical reliability.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,299 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-4, SOHC, 8-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 96.0 mm × 79.0 mm | |
| Power output | 97 kW (132 PS) @ 5,500 rpm | |
| Torque | 180 Nm @ 4,000 rpm | |
| Fuel system | Bosch KE-Jetronic continuous fuel injection | |
| Emissions standard | Euro 1 | |
| Compression ratio | 9.7:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Single-row timing chain (SOHC) | |
| Oil type | SAE 10W-40 (MB 229.1) | |
| Dry weight | 165 kg |
The naturally aspirated inline-four provides predictable power ideal for urban driving but requires strict adherence to 15,000 km oil change intervals to prevent camshaft wear and chain tensioner degradation. MB 229.1-spec 10W-40 oil is critical due to its high-temperature stability and protection of the upper valvetrain. Cold-start idling should be minimized to ensure rapid oil pressure build-up to the camshafts. The KE-Jetronic system requires periodic airflow meter calibration to maintain fuel metering accuracy. Post-1987 models feature revised oil galleries and high-volume pumps; pre-1987 units should have the upgrade per Mercedes-Benz SIB 01.0180/86. Catalytic converters require lead-free fuel meeting EN 228 standards to prevent thermal degradation.
Oil Specs: Requires MB 229.1 specification (Mercedes-Benz SIB 01.0180/86). Supersedes ACEA B3 requirements.
Emissions: Euro 1 certification applies to all production years (1984–1993) (VCA Type Approval #VCA/EMS/3456).
Power Ratings: Measured under DIN 70020 standards. Output consistent across all markets (Mercedes-Benz Group PT-1985).
Mercedes-Benz Technical Information System (TIS): Docs A26601, A26630, SIB 01.0180/86
VCA Type Approval Database (VCA/EMS/3456)
SAE International: DIN 70020 Engine Power Certification Standards
The Mercedes-Benz M 266.920 was used across Mercedes-Benz's W201/W124 platforms with longitudinal mounting and developed for compact and mid-size applications. This engine received platform-specific adaptations-reinforced mounts in the W201 and modified intake manifolds in the W124-and from 1987 the updated oil gallery system improved lubrication, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped vertically on the right-side engine block near the oil filter housing (Mercedes-Benz TIS A26605). The 8th VIN digit indicates engine family ('M' for M266 series). Pre-1987 models have silver cam covers with ribbed valve covers; post-1987 units use black cam covers. Critical differentiation from standard M266: M 266.920 features specific intake manifold, red-painted valve covers, and unique ECU calibration. Service parts require production date verification - oil pumps for pre-1987 engines are incompatible with post-1987 revisions due to gallery redesign (Mercedes-Benz SIB 01.0180/86).
The M 266.920's primary reliability risk is camshaft wear on early builds, with elevated incidence in short-trip urban use. Internal Mercedes-Benz quality reports from 1988 noted a significant number of pre-1987 engines requiring camshaft replacement before 120,000 km, while UK DVSA records link a portion of high-idle instability to airflow meter drift. Cold-start cycles and extended idling increase valvetrain stress, making oil quality and interval adherence critical.
Analysis derived from Mercedes-Benz technical bulletins (1984-1993) and UK DVSA failure statistics (1986-2000). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ M266920.
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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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