The Fiat 156 A3.000 is a 1,586 cc, inline-four, naturally aspirated petrol engine produced between 1985 and 1992. It features a single overhead camshaft (SOHC), 8-valve configuration, and carburetted fuel delivery. In standard tune, it delivers 56 kW (76 PS), offering improved torque and drivability over smaller Fiat engines in its class.
Fitted primarily to the Fiat Regata 75 and Lancia Thema 1.6, the 156 A3.000 was engineered for balanced performance and durability in mid-size sedans. Emissions compliance was achieved through a basic crankcase ventilation system and precise carburettor calibration, meeting Euro 0 standards. The engine was designed for longitudinal mounting in Fiat’s Tipo-derived 156 platform.
One documented service concern involves intake manifold cracking near the thermostat housing, particularly in vehicles subjected to frequent thermal cycling. This issue, referenced in Fiat Service Information Bulletin 85-072, is attributed to material fatigue in early castings. Later production units incorporated a revised alloy composition and thicker flange design to improve durability.
Production years 1985–1992 meet Euro 0 emissions standards (EU Directive 83/351/EEC). Vehicle-specific compliance confirmed via historical EU type approval records.
The Fiat 156 A3.000 – Petrol is a 1,586 cc inline-four SOHC engine developed for mid-size sedans (1985–1992). It uses a carburetted fuel system and simple valvetrain to deliver reliable performance. Designed for longitudinal installation, it complies with early European emissions directives while maintaining mechanical simplicity.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,586 cc | |
| Fuel type | Petrol (Unleaded RON 95) | |
| Configuration | Inline-4, SOHC, 8-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 80.0 mm × 79.0 mm | |
| Power output | 56 kW (76 PS) @ 5,600 rpm | |
| Torque | 118 Nm @ 3,200 rpm | |
| Fuel system | Weber 34 ADM carburettor | |
| Emissions standard | Euro 0 | |
| Compression ratio | 9.2:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Chain-driven (SOHC) | |
| Oil type | SAE 10W-40, API SF/CC | |
| Dry weight | 104 kg |
The naturally aspirated design with carburettor provides predictable power delivery ideal for city and highway driving, but requires periodic adjustment to maintain idle stability and fuel economy. SAE 10W-40 mineral oil meeting API SF/CC is essential for valvetrain protection, especially given the engine's sensitivity to oil degradation. Oil changes should occur every 7,500 km to prevent accelerated wear. The Weber 34 ADM carburettor is sensitive to fuel quality and should be cleaned every 15,000 km to prevent clogging. Units produced before mid-1987 should be inspected for intake manifold cracks per Fiat SIB 85-072, and revised manifolds with reinforced flanges are available as OEM replacements.
Oil Specs: Requires SAE 10W-40, API SF/CC specification (Fiat SIB 85-072). Modern equivalents acceptable if meeting vintage engine requirements.
Emissions: Euro 0 certification applies to all 1985–1992 models (EU Directive 83/351/EEC). No catalytic converter fitted in standard configurations.
Power Ratings: Measured under ISO 1585 standards. Output unchanged across production run; no performance variants documented.
Fiat Technical Information System (TIS): Docs 156A3000-ARCH-03, 156A3000-MECH-05, SIB 85-072
European Commission: Directive 83/351/EEC - Emissions Standards for Light-Duty Vehicles
Fiat Parts Catalogue (ETK): Engine Family 156 Series
ISO 1585:1982 - Road Vehicles — Test Method for Fuel Consumption
The Fiat 156 A3.000 – Petrol was used across Fiat's 156 platform with longitudinal mounting and front-wheel drive. This engine received platform-specific adaptations—carburettor jetting variations for high-altitude markets—and from 1988, the facelifted Regata SLX models adopted revised ignition timing curves, creating minor tuning differences. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped vertically on the left-side engine block near the exhaust manifold (Fiat TIS 156A3000-ID-12). The 8th VIN digit indicates engine type ('A' for 1.6L 76 PS). Pre-1987 models use a chrome valve cover; post-1987 units have a black painted cover. Critical differentiation from 154 C4.046: 156 A3.000 has a larger bore (80.0 mm) and uses a Weber 34 ADM carburettor, while 154 C4.046 is fuel-injected. Service parts require model year verification—intake manifolds before 07/1987 are non-interchangeable with later reinforced versions per Fiat SIB 85-072.
The 156 A3.000 – Petrol's primary reliability risk is intake manifold cracking on early builds, with elevated incidence in vehicles used in stop-start urban environments. Internal Fiat service reports from 1987 indicated a significant portion of pre-1987 engines required manifold replacement before 90,000 km, while historical EU field data shows carburettor-related drivability issues were common in coastal regions with high humidity. Extended oil intervals and low-quality fuel amplify wear, making adherence to service schedules and fuel quality critical.
Analysis derived from Fiat technical bulletins (1985-1992) and European Commission field reliability reports (1986-1993). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about FIAT 156-A3-000.
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