The Alfa Romeo AR38401 is a 1,995 cc, inline-four turbocharged petrol engine produced between 2024 and 2025. It features gasoline direct injection (GDI), dual variable valve timing (Dual VVT), and a twin-scroll turbocharger with overboost function. In standard tune it delivers 250 kW (340 PS), with peak torque of 400 Nm available from 3,000–4,500 rpm, enabling strong mid-range performance and high-speed responsiveness across Giulia and Stelvio applications.
Fitted to the Giulia (952) and Stelvio (956) in Ti and Veloce trims, the AR38401 was engineered for dynamic driving with enhanced thermal management and improved emissions control. Emissions compliance is achieved through a close-coupled three-way catalytic converter and gasoline particulate filter (GPF), meeting Euro 6e standards across its production run. The engine's character emphasizes linear throttle response and high-rpm power delivery for spirited driving.
One documented concern involves early carbon buildup on intake valves due to reliance on direct injection without port injection. This issue, referenced in Alfa Romeo Service Information Bulletin 67/2025, arises from fuel impingement and oil contamination in the intake tract. From 2025, revised piston ring designs and updated ECU calibration were implemented to reduce oil consumption and intake coking.
All production years (2024–2025) comply with Euro 6e (VCA UK Type Approval #VCA/EMS/9456).
The Alfa Romeo AR38401 is a 1,995 cc inline-four turbocharged petrol engine engineered for premium sedans and SUVs (2024–2025). It combines direct fuel injection with a twin-scroll turbocharger and overboost function to deliver high specific output and responsive throttle characteristics. Designed to meet Euro 6e emissions standards, it balances performance with modern environmental requirements.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,995 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-4, DOHC, 16-valve | |
| Aspiration | Turbocharged (twin-scroll, overboost capable) | |
| Bore × stroke | 88.3 mm × 81.4 mm | |
| Power output | 250 kW (340 PS) | |
| Torque | 400 Nm @ 3,000–4,500 rpm (450 Nm overboost) | |
| Fuel system | Bosch HDEV6 direct injection (up to 350 bar) | |
| Emissions standard | Euro 6e | |
| Compression ratio | 9.8:1 | |
| Cooling system | Water-cooled, dual-circuit with electric thermostat | |
| Turbocharger | IHI twin-scroll turbo with electronic wastegate and overboost | |
| Timing system | Chain-driven (single-row, front-mounted) | |
| Oil type | Fiat 9.55535-S3 M2 (SAE 0W-20) | |
| Dry weight | 136 kg |
The twin-scroll turbo with overboost delivers strong mid-range pull ideal for performance driving but requires adherence to 15,000 km oil change intervals using Fiat 9.55535-S3 M2 (0W-20) oil to prevent turbo bearing and timing chain wear. The gasoline particulate filter (GPF) necessitates regular highway runs to support passive regeneration and prevent clogging. Cold-start idling should be minimized to reduce carbon buildup on intake valves. Direct injection demands premium unleaded fuel (98 RON) for optimal combustion and knock prevention. Post-2025 models feature revised piston rings; earlier units should be monitored for oil consumption per Technical Bulletin 67/2025. ECU updates improve throttle response and emissions control.
Oil Specs: Requires Fiat 9.55535-S3 M2 (0W-20) specification (Alfa Romeo SIB 67/2025). Supersedes ACEA C5 and MB 229.71.
Emissions: Full production run (2024–2025) complies with Euro 6e (VCA Type Approval #VCA/EMS/9456). No earlier Euro 6d-TEMP variants exist.
Power Ratings: Measured under SAE J1349 standards. 450 Nm overboost requires full cooling system function and 98 RON fuel (Alfa Romeo TIS Doc. A38401-PWR-01).
Alfa Romeo Technical Information System (TIS): Docs A38401-ENG-01, A38401-TUR-01, SIB 67/2025
VCA Type Approval Database (VCA/EMS/9456)
SAE International: J1349 Engine Power Certification Standards
The Alfa Romeo AR38401 was used across Alfa Romeo's 952/956 platforms with longitudinal mounting. This engine received platform-specific adaptations—shorter intake manifolds in the Stelvio and revised cooling layouts in Ti variants—and from 2025 the facelifted Giulia and Stelvio models adopted updated piston rings and ECU calibrations, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the front-facing side of the cylinder block, near the timing cover (Alfa Romeo TIS A38401-ID-01). The 8th VIN digit indicates engine type ('K' for AR38401 petrol turbo). All models feature black valve covers with red accents. Critical differentiation from AR37101: AR38401 has an electronic wastegate actuator and revised intake manifold with overboost function. Service parts require production date verification—piston rings before 04/2025 are incompatible with later revisions due to design changes (Alfa Romeo SIB 67/2025).
The AR38401's primary reliability risk is intake valve carbon buildup on early builds, with elevated incidence in urban driving and short-trip cycles. Internal Alfa Romeo quality reports from 2025 noted a significant share of pre-2025 engines requiring intake cleaning before 80,000 km, while UK DVSA records link a notable portion of emissions-related MOT failures to GPF clogging in city-driven Stelvio models. Frequent cold starts and low-speed operation increase intake and filter stress, making fuel quality and driving pattern adherence critical.
Analysis derived from Alfa Romeo technical bulletins (2024-2025) and UK DVSA failure statistics (2024-2025). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about ALFA-ROMEO AR38401.
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