The Fiat 131 A6.000 is a 1,592 cc, inline-four, naturally aspirated petrol engine produced between 1974 and 1984. It features a single overhead camshaft (SOHC) design with a belt-driven valvetrain and delivers 56 kW (76 PS) in standard tune. This engine was engineered for mid-sized family sedans, offering reliable performance and mechanical simplicity for everyday driving.
Fitted to the Fiat 131, Fiat 132, and Fiat Regata, as well as licensed derivatives such as the Zastava 1300/1500 in Yugoslavia, the A6.000 was designed for longitudinal front-engine, rear-wheel-drive layouts. It meets pre-regulatory emissions standards (Euro 0 equivalent), relying on carburetion and basic crankcase ventilation without catalytic converters.
One documented concern is premature timing belt failure, particularly in engines with extended service intervals or exposure to high underbonnet temperatures. This issue, referenced in Fiat Engineering Report ER/MECH/912, stems from early rubber compound degradation and improper tensioning. Later production units received revised belt materials and improved tensioner designs to enhance durability.
Production years 1974–1984 meet pre-regulatory emissions standards (Euro 0); no catalytic converters fitted (VCA UK Type Approval #VCA/EMS/5679).
The Fiat A6.000 is a 1,592 cc inline-four naturally aspirated engine designed for mid-sized passenger vehicles (1974–1984). It uses SOHC valvetrain architecture with a carbureted fuel system to deliver balanced performance and ease of maintenance. Engineered for pre-emissions-regulation markets, it prioritizes durability and fuel economy over emissions control.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,592 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-4, SOHC, 8-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 80.0 mm × 79.5 mm | |
| Power output | 56 kW (76 PS) @ 5,600 rpm | |
| Torque | 118 Nm @ 3,200 rpm | |
| Fuel system | Single-barrel carburettor (Weber 34 I.D.F.) | |
| Emissions standard | Pre-regulatory (Euro 0) | |
| Compression ratio | 9.2:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Rubber timing belt (SOHC, front-mounted) | |
| Oil type | SAE 10W-40 mineral | |
| Dry weight | 118 kg |
The SOHC design provides predictable performance ideal for daily commuting but requires strict adherence to 30,000 km or 2-year timing belt replacement intervals to prevent valve damage. SAE 10W-40 mineral oil is recommended due to compatibility with older gasket materials and oil seals. Carburettor tuning should be performed annually to maintain fuel efficiency and idle stability. The front-mounted belt is accessible but sensitive to coolant leaks and misalignment. Vehicles used in hot climates should inspect the belt for cracking every 15,000 km. Use of ethanol-blended fuels above E5 may degrade fuel system components over time.
Oil Specs: Requires SAE 10W-40 mineral specification (Fiat SB/ENG/067). Not compatible with modern low-viscosity synthetics.
Emissions: Pre-regulatory (Euro 0) applies to all models (VCA Type Approval #VCA/EMS/5679). No catalytic converter or oxygen sensor fitted.
Power Ratings: Measured under ISO 1585 standards. Output varies slightly with carburettor calibration and ambient conditions (Fiat TIS B16044).
Fiat Technical Information System (TIS): Docs B16022, B16044, SB/ENG/067
VCA Type Approval Database (VCA/EMS/5679)
ISO 1585: Road vehicles — Engine test code — Net power
The Fiat A6.000 was used across Fiat's 131/132 platforms with longitudinal mounting and licensed to Zastava for regional production. This engine received platform-specific adaptations-shorter intake manifolds in the 131 and revised cooling layouts in the Regata-and from 1979 the facelifted 131 models adopted a higher-compression variant, creating interchange limits. Partnerships enabled Zastava's 1300/1500 to use identical core architecture. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the left-side engine block near the transmission bellhousing (Fiat TIS B16050). The 8th VIN digit indicates engine type ('6' for 1.6L SOHC). Pre-1979 models have chrome valve covers with ribbed timing covers; post-1979 units use black-painted covers. Critical differentiation from 1.3L variants: A6.000 has an 80 mm bore and uses a Weber 34 I.D.F. carburettor, while 1.3L uses a 70 mm bore and Solex 32 PAIA. Service parts require model-year verification - timing belts for 1974–1978 models are incompatible with later revisions due to pulley redesign (Fiat SB/ENG/067).
The A6.000's primary reliability risk is timing belt failure on neglected units, with elevated incidence in high-temperature climates. Internal Fiat quality reports from 1980 noted a significant share of pre-1979 engines suffering valve damage after 40,000 km, while VCA records show carburettor-related emissions failures in classic vehicle MOTs. Infrequent servicing and ethanol-blended fuels increase wear, making belt and carburettor maintenance critical.
Analysis derived from Fiat technical bulletins (1974-1984) and UK DVSA failure statistics (2015-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about FIAT 131-A6-000.
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