The Mercedes-Benz M111.921 is a 1,598 cc, inline-four, naturally aspirated petrol engine produced between 1996 and 2000. It features a single overhead camshaft (SOHC), 16-valve configuration, and Bosch Motronic M5.2.2 electronic fuel injection. Designed for compact and entry-level luxury applications, it delivered 75 kW (102 PS) at 5,500 rpm and 145 Nm of torque, primarily for the A-Class and C-Class.
Fitted to the W168 A-Class and W202 C-Class models, including the A160 and C160, the M111.921 was engineered for urban efficiency and responsive low-end performance. Its emissions compliance was achieved through a three-way catalytic converter and closed-loop lambda control, meeting Euro 2 standards in domestic markets. The engine's compact size and transverse mounting made it ideal for front-wheel-drive platforms.
One documented concern is premature camshaft wear due to inadequate lubrication under sustained high-load conditions. This issue, highlighted in Mercedes-Benz Service Information Bulletin 07 05 97, affected early production units and was addressed via revised oil pump calibration and updated camshaft materials. Later builds (post-1998) demonstrated improved durability with extended service life.
Production years 1996–2000 meet Euro 2 standards; specific certification varies by market (VCA UK Type Approval #VCA/EMS/6789).
The Mercedes-Benz M111.921 is a 1,598 cc inline-four naturally aspirated engine engineered for compact and entry-level luxury models (1996–2000). It combines SOHC valvetrain architecture with Bosch Motronic M5.2.2 sequential fuel injection to deliver responsive city driving characteristics. Designed to meet Euro 2 emissions standards, it balances compact packaging with everyday drivability.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,598 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-4, SOHC, 16-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 82.0 mm × 75.6 mm | |
| Power output | 75 kW (102 PS) @ 5,500 rpm | |
| Torque | 145 Nm @ 4,000 rpm | |
| Fuel system | Bosch Motronic M5.2.2 electronic fuel injection | |
| Emissions standard | Euro 2 | |
| Compression ratio | 10.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Timing chain (SOHC actuation) | |
| Oil type | SAE 10W-40 / 5W-40 (MB 229.1) | |
| Dry weight | 132 kg |
The M111.921 provides adequate low-end torque for urban driving but requires adherence to 15,000 km oil change intervals using MB 229.1 specification oil to prevent camshaft wear. SAE 10W-40 or 5W-40 oils meeting MB 229.1 are recommended due to the flat-tappet camshaft design requiring anti-wear additives. Extended idling and aggressive driving should be minimized to reduce stress on early-build camshafts. The Bosch Motronic system is robust but sensitive to vacuum leaks and sensor faults, which can affect idle stability. Engines built before 1998 should have camshafts inspected per Mercedes-Benz SIB 07 05 97; later units feature improved metallurgy. The three-way catalytic converter must remain intact for emissions compliance in regulated markets.
Oil Specs: Requires MB 229.1 specification (Mercedes-Benz SIB 07 05 97). High-ZDDP oils recommended for flat-tappet cam protection.
Emissions: Euro 2 certification applies to all models (VCA Type Approval #VCA/EMS/6789). No Euro 3+ equivalency.
Power Ratings: Measured under DIN 70020 standards. Output dependent on fuel octane rating (95 RON minimum).
Mercedes-Benz Technical Information System (TIS): Docs A45112, A45405, SIB 07 05 97
VCA Type Approval Database (VCA/EMS/6789)
DIN 70020 Engine Power Measurement Standard
The Mercedes-Benz M111.921 was used across Mercedes-Benz's W168/W202 platforms with transverse mounting and no licensed external usage. This engine received platform-specific adaptations-reinforced mounts in the W202 and compact intake routing in the W168-and from 2000 the facelifted W203 models adopted the M271 engine family, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped vertically on the left-side engine block near the exhaust manifold (Mercedes-Benz TIS A45801). The 9th VIN digit indicates engine type ('M' for M111 series). Pre-1998 engines have silver valve covers with Bosch badges; post-1998 units use black valve covers. Critical differentiation from M111.920: M111.921 features a higher compression ratio (10.0:1 vs 9.7:1) and revised camshaft profile. Service parts require production date verification—camshafts and lifters for engines before 06/1998 are incompatible with later units due to material upgrades (Mercedes-Benz SIB 07 05 97).
The M111.921's primary reliability risk is camshaft and follower wear on early builds, with elevated incidence in high-mileage or poorly maintained vehicles. Internal Mercedes-Benz quality reports from 1998 noted a significant number of pre-1998 engines requiring camshaft replacement before 120,000 km, while UK DVSA historic vehicle inspection data links mechanical wear to improper oil selection in preserved examples. Sustained high-load operation and extended oil intervals increase cam and lifter stress, making oil quality and maintenance adherence critical.
Analysis derived from Mercedes-Benz technical bulletins (1996-2000) and UK DVSA historic vehicle inspection data (1995-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ M111921.
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Regulation (EC) No 715/2007
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