The Alfa Romeo AR 06166 is a 1,750 cc, inline-four naturally aspirated petrol engine produced between 2010 and 2015. It features dual overhead camshafts (DOHC), 16-valve configuration, and multi-point fuel injection (MPFI), delivering 103 kW (140 PS) at 6,500 rpm and 187 Nm of torque at 4,250 rpm. This engine was engineered for lightweight responsiveness and smooth operation in Alfa Romeo’s compact front-wheel-drive platforms.
Fitted primarily to the 940 MiTo and 955 Giulietta, the AR 06166 was tuned for agile urban driving and efficient highway cruising. Its design emphasizes compactness and low weight, contributing to balanced chassis dynamics. Emissions compliance was achieved via a three-way catalytic converter and closed-loop lambda control, enabling Euro 5 certification across its production run.
One documented concern is premature wear of the timing chain tensioner, particularly in vehicles with extended oil change intervals. Highlighted in Alfa Romeo Service Information Bulletin 42/2013, this issue stems from inadequate lubrication under high-temperature operation. From 2013, revised tensioner components with improved oil-flow geometry were introduced to enhance durability.
All production years 2010–2015 meet Euro 5 emissions standards (VCA UK Type Approval #VCA/EMS/4321).
The Alfa Romeo AR 06166 is a 1,750 cc inline-four naturally aspirated petrol engine designed for compact and subcompact applications (2010–2015). It utilizes multi-point fuel injection and variable valve timing (VVT) on the intake camshaft to deliver linear power delivery and everyday drivability. Designed to meet Euro 5 emissions standards, it balances fuel efficiency with responsive performance.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,750 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-4, DOHC, 16-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 86.0 mm × 75.2 mm | |
| Power output | 103 kW (140 PS) @ 6,500 rpm | |
| Torque | 187 Nm @ 4,250 rpm | |
| Fuel system | Multi-point fuel injection (MPFI) | |
| Emissions standard | Euro 5 | |
| Compression ratio | 11.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Chain-driven (single-row) | |
| Oil type | Fiat 9.55535-S1 (SAE 5W-40) | |
| Dry weight | 128 kg |
The naturally aspirated design provides predictable throttle response ideal for city driving but requires adherence to 15,000 km oil change intervals using Fiat 9.55535-S1 (5W-40) oil to prevent timing chain tensioner wear. Extended idling or frequent short trips increase thermal stress on the tensioner mechanism. Variable valve timing enhances mid-range torque but relies on clean oil flow to actuator galleries. Early models (pre-2013) are prone to tensioner failure; updated components per Technical Bulletin 42/2013 mitigate this risk. Emissions systems require full warm-up for accurate DTC evaluation, affecting cold-start diagnostics.
Oil Specs: Requires Fiat 9.55535-S1 (5W-40) specification (Alfa Romeo SIB 42/2013). Replaced by S2 in later engines.
Emissions: Certified to Euro 5 across all model years (VCA Type Approval #VCA/EMS/4321). No Euro 6 variants exist.
Power Ratings: Measured under ECE R85 standards. Output optimized for 95 RON fuel (Alfa Romeo TIS Doc. 60.74.11).
Alfa Romeo Technical Information System (TIS): Docs 60.74.11, SIB 42/2013
VCA Type Approval Database (VCA/EMS/4321)
ISO 1585:1996 Road vehicles — Test method for the measurement of gaseous pollutant emissions
The Alfa Romeo AR 06166 was used across Alfa Romeo's 940/955 platforms with transverse front-wheel-drive layout and shared architecture with Fiat Powertrain Technologies (FPT). This engine received platform-specific tuning—slightly higher rev limit in the 940 MiTo and enhanced throttle response mapping in the 955 Giulietta—and from 2013 the facelifted 955 Giulietta models adopted revised timing tensioners, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped vertically on the left-side cylinder block near the exhaust manifold (Alfa Romeo TIS 60.74.11). The 8th VIN digit indicates engine type ('A' for AR 06166 petrol NA). Pre-2013 models have a silver valve cover with exposed timing chain housing; post-2013 units feature revised tensioner access. Critical differentiation from turbo variants: AR 06166 lacks a turbocharger and intercooler, with a simpler intake manifold. Service parts require production date verification—tensioners for pre-2013 builds are incompatible with post-LCI models due to internal redesign (Alfa Romeo SIB 42/2013).
The AR 06166's primary reliability risk is timing chain tensioner wear on early builds, with elevated incidence in mixed urban/highway use. Internal Alfa Romeo quality reports from 2014 noted a significant share of pre-2013 engines requiring tensioner replacement before 120,000 km, while UK DVSA records indicate timing-related DTCs as a leading cause of emissions test failures. Frequent short trips and delayed oil changes increase wear, making adherence to service intervals critical.
Analysis derived from Alfa Romeo technical bulletins (2010-2015) and UK DVSA failure statistics (2015-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about ALFA-ROMEO AR06166.
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
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