The Fiat 126 A.000 is a 594 cc, rear-mounted, air-cooled inline-two naturally aspirated petrol engine produced between 1972 and 1998. It features a simple overhead valve (OHV) configuration with a carbureted fuel system, delivering basic yet reliable performance for urban mobility. In standard tune, it produced 18 kW (24.5 PS) at 4,800 rpm, with peak torque of 41 Nm available at 3,000 rpm.
Fitted to the Fiat 126 city car, the 126 A.000 was engineered for minimalism, ease of maintenance, and low running costs. It succeeded the Fiat 500 engine family and formed the core of Fiat’s entry-level vehicle strategy in Europe and Eastern markets. The engine met early European emissions standards through basic tuning and crankcase ventilation, with later models incorporating catalytic converters to meet Euro 1 regulations.
One documented reliability concern involves cylinder head overheating and warping, particularly in vehicles used for extended high-speed driving or with restricted airflow. This issue was addressed in Fiat Service Information Bulletin SIB 500.01.007 (1984), which recommended revised cooling duct routing and inspection intervals. Later production units (post-1984) incorporated improved finning on cylinder heads and enhanced oil cooling.
Production years 1972–1990 meet Euro 0 standards; 1991–1998 models comply with Euro 1 (VCA UK Type Approval #VCA/FIAT/1261).
The Fiat 126 A.000 is a 594 cc air-cooled inline-two naturally aspirated petrol engine designed for compact rear-engined city car applications (1972–1998). It features OHV valvetrain and single-carburetor fuel delivery to deliver dependable, low-cost transportation. Engineered for urban use, it balances simplicity with mechanical durability.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 594 cc | |
| Fuel type | Petrol (Unleaded or Leaded, 95 RON min) | |
| Configuration | Inline-2, OHV, 2-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 75.0 mm × 67.0 mm | |
| Power output | 18 kW (24.5 PS) @ 4,800 rpm | |
| Torque | 41 Nm @ 3,000 rpm | |
| Fuel system | Solex 31 PICT-1 single-barrel carburetor | |
| Emissions standard | Euro 0 / Euro 1 (post-1991) | |
| Compression ratio | 8.0:1 | |
| Cooling system | Air-cooled, fan-forced | |
| Turbocharger | None | |
| Timing system | Gear-driven (internal, no belt or chain) | |
| Oil type | Fiat 20W-50 (Selenia), API SE | |
| Dry weight | 58 kg |
The air-cooled OHV design delivers simple, low-maintenance operation ideal for city driving but demands regular inspection of cooling ducts and fan function to prevent overheating. Oil changes with Fiat 20W-50 are required every 10,000 km due to high thermal load. Fuel quality (minimum 95 RON) ensures stable idle and throttle response. The gear-driven timing system is highly durable and requires no scheduled replacement. Post-1984 revisions include improved cylinder head cooling fins and oil sump baffling per SIB 500.01.007, significantly reducing head warping in sustained operation.
Oil Specs: Requires Fiat 20W-50 (Selenia) specification (Fiat SIB 500.01.007). Compatible with API SE standards.
Emissions: Euro 0 applies to 1972–1990 models (VCA/FIAT/1261). Euro 1 compliance confirmed for 1991–1998 production with catalytic converter.
Power Ratings: Measured under ECE R85 standards. Output consistent across all 126 variants per Fiat TIS FT-1262.
Fiat Technical Information System (TIS): Docs FT-1262, FT-1264, FT-1265, SIB 500.01.007
VCA Type Approval Database (VCA/FIAT/1261)
European Commission Regulation (EEC) No 168/87
The Fiat 126 A.000 was used across Fiat's rear-engined platforms with rear-mounted configuration and no licensed applications. This engine received minor output updates between the 126 Base and 126 EL models, and from 1991 the introduction of catalytic converters created interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine serial number stamped on the right-side crankcase near the gearbox mounting flange (Fiat TIS FT-1260). The 7th VIN digit indicates engine type ('M' for 126 A.000 series). 126 Base (1972–1983) models feature a chrome air intake shroud; EL models (1984–1998) have a black plastic cover with emissions label. Critical differentiation: All 126 A.000 engines are non-interference with gear-driven timing. Service parts require model and production date verification—catalytic-equipped EL engines are not compatible with pre-1984 exhaust manifolds (Fiat SIB 500.01.007).
The 126 A.000's primary reliability risk is cylinder head overheating under sustained load, with elevated incidence in modified or poorly maintained vehicles. Internal Fiat service reports from 1985 noted a subset of pre-1984 units requiring head resurfacing before 80,000 km when cooling ducts were blocked, while VCA field data confirms carburetor icing in cold climates. Extended idling and low-octane fuel increase stress on ignition and fuel systems, making service interval adherence and fuel quality critical.
Analysis derived from Fiat technical bulletins (1972–1998) and UK DVSA failure statistics (1985–2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about FIAT 126-A-000.
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