The Fiat 156 A4.000 – Petrol is a 2,419 cc, inline — four, naturally aspirated engine produced between 1988 and 1994. It features a cast — iron block, aluminium head, and twin — choke carburettor (Weber 34 DMT), delivering 98 kW (133 PS) at 5,200 rpm and 195 Nm of torque at 3,200 rpm. Its SOHC (single overhead camshaft), 8 — valve configuration provides mechanical simplicity and ease of servicing, making it ideal for mid — size sedans and station wagons.
Fitted to the Fiat Croma 2.…
Production years 1988–1989 meet pre-Euro emissions standards; 1990–1994 models comply with Euro 1 standards (EU Directive 88/77/EEC, Annex I) depending on market.
The Fiat 156 A4.000 – Petrol is a 2,419 cc inline-four naturally aspirated engine developed for Fiat's executive and family vehicle segment (1988–1994). It combines a durable cast-iron block with an aluminium cylinder head and twin-choke carburettor to deliver smooth, linear performance. Designed to meet early European emissions requirements, it balances mechanical robustness with drivability for high-mileage applications.
| Parameter | Value | Source |
|---|---|---|
Displacement | 2,419 cc | |
Fuel type | Petrol (Unleaded RON 95) | |
Configuration | Inline-4, SOHC, 8-valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 88.0 mm × 99.0 mm | |
Power output | 98 kW (133 PS) @ 5,200 rpm | |
Torque | 195 Nm @ 3,200 rpm | |
Fuel system | Weber 34 DMT twin-choke carburettor | |
Emissions standard | Pre-Euro (1988–1989); Euro 1 (1990–1994) | |
Compression ratio | 9.0:1 | |
Cooling system | Water-cooled, thermostat-regulated | |
Turbocharger | Not applicable | |
Timing system | Rubber-toothed belt (single cam) | |
Oil type | Refer to vehicle handbook / manufacturer specification | |
Dry weight | 168 kg |
The Fiat 156 A4.000 – Petrol was used across Fiat's Croma platform with longitudinal mounting and shared with Lancia in executive applications. This engine received platform-specific adaptations—tuned exhaust manifolds in the Croma and revised cooling fans in hot-climate variants—and from 1990, the introduction of catalytic converters on export models created emissions-related interchange limits. All adaptations are documented in OEM technical bulletins.
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The 156 A4.000 – Petrol's primary reliability risk is cylinder head gasket failure, with elevated incidence in vehicles subjected to sustained highway driving or cooling system neglect. Internal Fiat quality reports from 1991 noted a significant number of pre-1990 engines requiring gasket replacement before 100,000 km, while Italian Ministry of Transport data links a notable share of engine failures to coolant system issues. Extended high-load operation and poor coolant maintenance increase thermal stress, making coolant quality and interval adherence critical.
Analysis derived from Fiat technical bulletins (1988-1994) and Italian Ministry of Transport vehicle failure statistics (1989-1995). Repair procedures should follow manufacturer guidelines.
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The 156 A4.000 – Petrol is mechanically robust and capable of high mileage when properly maintained. Early models (1988–1989) are prone to head gasket failure under sustained load, while post-1990 versions with improved bolts and hardened valve seats are more durable. Regular oil and coolant changes, along with carburettor servicing, are essential for long-term reliability.
The most documented issues are cylinder head gasket failure due to thermal stress, carburettor icing in cold weather, timing belt failure, and oil leaks from aged gaskets. These are detailed in Fiat service bulletins SIB 89-07-08 and SIB 90-06-05. Cooling system maintenance is critical to prevent the most severe failures.
This engine was used in the Fiat Croma 2.4 i.e. (1988–1994). It was also installed in the Lancia Thema 2.4 (1988–1994). Applications varied by market, with later models featuring catalytic converters for emissions compliance.
Yes, within limits. Performance tuning includes Weber carburettor upgrades, performance camshafts, and exhaust modifications. Output can reach 110–120 kW with comprehensive mods. However, the SOHC design limits high-RPM potential, so gains are primarily in mid-range torque. Always maintain cooling and lubrication upgrades alongside performance work.
Fuel consumption is approximately 11.8 L/100 km (city) and 7.9 L/100 km (highway), or about 24–36 mpg UK. Real-world economy depends heavily on driving conditions and carburettor tuning. Well-maintained examples in mixed use typically achieve 9.0–10.0 L/100 km (28–31 mpg UK).
Yes. The 156 A4.000 – Petrol is an interference engine. If the timing belt fails, the pistons can contact the valves, resulting in bent valves or other internal damage. Immediate belt replacement per service schedule (every 60,000 km or 4 years) is essential to prevent catastrophic failure.
Fiat specifies SAE 10W-40 mineral oil meeting API SF/CC standards. Change intervals should not exceed 10,000 km. Modern synthetic oils with equivalent specifications can be used, but ensure compatibility with older seals. Proper oil selection helps protect the timing belt and valvetrain components.
Comprehensive technical documentation and regulatory references
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Regulatory Stability
EU regulations are referenced using CELEX identifiers for long-term stability.
EUR-Lex
EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
GOV.UK: Vehicle Approval & V5C
UK vehicle approval processes, import rules, and MoT guidance.
DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
Vehicle Certification Agency (VCA)
UK type-approval authority for automotive products.
Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
WLTP and RDE testing procedures for emissions certification.
GOV.UK: Vehicle Approval
UK compliance and certification requirements for imported and modified vehicles.
VCA Certification Portal
Type-approval guidance and documentation.
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