The Fiat 159 A4.000 is a 1,586 cc, inline-four, naturally aspirated petrol engine produced between 1987 and 1995. It features a single overhead camshaft (SOHC), 8-valve configuration, and electronic fuel injection via a Magneti Marelli IAW 1AV system. In standard tune, it delivers 57 kW (78 PS), offering improved drivability and emissions control over earlier carburetted variants.
Fitted primarily to the Fiat Croma 1.6 i.e. and Lancia Delta II 1.6 i.e., the 159 A4.000 was engineered for balanced performance and durability in mid-size hatchbacks and sedans. Emissions compliance was achieved through a three-way catalytic converter and closed-loop lambda feedback, enabling Euro 1 compliance. The engine was designed for transverse front-wheel-drive installation across Fiat’s Type 159 platform.
One documented service concern involves premature wear of the hydraulic tappets, particularly in vehicles with extended oil change intervals. This issue, referenced in Fiat Service Information Bulletin 87-089, can lead to persistent valve train noise and reduced performance if undetected. From 1991, Fiat introduced a revised tappet design with improved oil retention to enhance long-term reliability.
Production years 1987–1990 meet Euro 0 standards; 1991–1995 models comply with Euro 1 (EU Directive 91/441/EEC). Vehicle-specific compliance confirmed via EU type approval records.
The Fiat 159 A4.000 – Petrol is a 1,586 cc inline-four SOHC engine developed for mid-size hatchbacks and sedans (1987–1995). It replaces carburetion with Magneti Marelli electronic fuel injection to improve emissions and throttle response. Designed for the Type 159 platform, it meets early Euro emissions standards while maintaining serviceability.
| 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 | 57 kW (78 PS) @ 5,600 rpm | |
| Torque | 120 Nm @ 3,200 rpm | |
| Fuel system | Magneti Marelli IAW 1AV electronic fuel injection | |
| Emissions standard | Euro 0 (1987–1990); Euro 1 (1991–1995) | |
| Compression ratio | 9.4:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Toothed belt (SOHC) | |
| Oil type | SAE 10W-40, API SG/CC | |
| Dry weight | 106 kg |
The naturally aspirated design with EFI provides smooth throttle response and improved cold-start reliability over carburetted engines. SAE 10W-40 oil meeting API SG/CC is essential for valvetrain protection, particularly given the engine's sensitivity to oil degradation. Oil changes should occur every 10,000 km to maintain lubrication integrity. The Magneti Marelli IAW 1AV system requires periodic injector cleaning and lambda sensor inspection to prevent drivability issues. Units produced before mid-1991 should have the hydraulic tappets inspected per Fiat SIB 87-089; the revised oil-retaining tappets are available as an OEM upgrade to prevent valve train noise and wear.
Oil Specs: Requires SAE 10W-40, API SG/CC specification (Fiat SIB 87-089). Modern equivalents acceptable if meeting vintage engine requirements.
Emissions: Euro 1 certification applies to 1991–1995 models only (EU Directive 91/441/EEC). Pre-1991 units meet Euro 0 and lack catalytic converters in some markets.
Power Ratings: Measured under ISO 1585 standards. Output unchanged across production run; no performance variants documented.
Fiat Technical Information System (TIS): Docs 159A4000-ARCH-03, 159A4000-MECH-05, SIB 87-089
European Commission: Directive 91/441/EEC - Emissions Standards for Passenger Cars
Fiat Parts Catalogue (ETK): Engine Family 159 Series
ISO 1585:1982 - Road Vehicles — Test Method for Fuel Consumption
The Fiat 159 A4.000 – Petrol was used across Fiat's Type 159 platform with transverse mounting and front-wheel drive. This engine received platform-specific adaptations—lambda sensor calibration differences for Lancia Delta II—and from 1991, the facelifted Fiat Croma models adopted the revised hydraulic tappets, 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 (Fiat TIS 159A4000-ID-12). The 8th VIN digit indicates engine type ('A' for 1.6L 78 PS). Pre-1991 models use a chrome valve cover; post-1991 units have a black painted cover. Critical differentiation from 156 A3.000: 159 A4.000 uses electronic fuel injection (IAW 1AV), while 156 A3.000 is carburetted. Service parts require model year verification—hydraulic tappets before 07/1991 are non-interchangeable with later revised units per Fiat SIB 87-089.
The 159 A4.000 – Petrol's primary reliability risk is hydraulic tappet wear on early builds, with elevated incidence in vehicles with irregular maintenance. Internal Fiat service reports from 1990 indicated a significant portion of pre-1991 engines required tappet replacement before 90,000 km, while historical EU field data shows lambda sensor-related emissions failures were common in high-mileage units. Extended service intervals and poor-quality fuel amplify wear, making adherence to maintenance schedules and fuel quality critical.
Analysis derived from Fiat technical bulletins (1987-1995) and European Commission field reliability reports (1988-1996). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about FIAT 159-A4-000.
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