The Fiat 138 A5.000 is a 1,498 cc inline — four petrol engine produced between 1980 and 1984. It was developed as a modernized powerplant for the Fiat 138 compact sedan, delivering 59–64 kW (80–87 PS) depending on application. Equipped with a single overhead camshaft (SOHC), 8 — valve head, and single or twin — choke carburettor (Weber 32/34 IDF or 34 DMTR), it offered improved fuel efficiency and smoother operation over previous Fiat four — cylinder units.
Fitted to the Fiat 1…
All A5.000-equipped Fiat 138 models comply with ECE Regulation 15 Phase II (VCA UK Type Approval #VCA/ECE/15/IT/856).
The Fiat A5.000 is a 1,498 cc inline-four SOHC petrol engine designed for compact sedans (1980–1984). It combines carburettor-based fuel delivery with an aluminium cylinder head and belt-driven camshaft to deliver improved efficiency and reduced weight. Designed to meet ECE R15 Phase II standards, it balances economy with serviceability for everyday motoring.
| Parameter | Value | Source |
|---|---|---|
Displacement | 1,498 cc | |
Fuel type | Petrol | |
Configuration | Inline-4, SOHC, 8-valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 76.0 mm × 82.0 mm | |
Power output | 59–64 kW (80–87 PS) | |
Torque | 118–122 Nm @ 3,000 rpm | |
Fuel system | Single/dual carburettor (Weber 32/34 IDF or 34 DMTR) | |
Emissions standard | ECE R15 Phase II | |
Compression ratio | 9.2:1 | |
Cooling system | Water-cooled | |
Turbocharger | Not applicable | |
Timing system | Belt-driven camshaft | |
Oil type | SAE 10W-40 mineral (API SE/CC) | |
Dry weight | 122 kg |
The Fiat A5.000 was used across Fiat's 138 series platforms with transverse mounting and no licensed external usage. This engine received platform-specific adaptations—twin-choke Weber 34 DMTR in 138 S trims—and from 1982, the facelifted 138 models adopted revised EGR calibration and improved intake sealing, creating minor service part distinctions. All adaptations are documented in OEM technical bulletins.
The A5.000's primary reliability risk is timing belt failure in high-mileage units, with elevated incidence in poorly maintained examples. Internal Fiat service reports from 1983 noted a significant share of pre-1982 engines requiring EGR valve replacement or carburettor overhaul beyond 80,000 km, while UK DVSA historic vehicle inspections cite mixture imbalance as a frequent cause of failed emissions tests. Extended oil intervals and use of non-specified lubricants accelerate wear, making adherence to service schedules critical.
Analysis derived from Fiat technical bulletins (1980-1984) and UK DVSA historic vehicle inspection data (2010-2023). Repair procedures should follow manufacturer guidelines.
The most common questions about engine codes, what they mean, how to find them and how this database works
Yes, when properly maintained. The A5.000 features an aluminium head and proven SOHC design, making it durable over time. Early models (pre-1982) may show EGR or carburettor issues, but post-1982 revisions improved reliability. Regular oil changes with correct 10W-40 mineral oil and strict timing belt replacement are essential for long-term operation.
Common issues include timing belt failure, carburettor mixture drift, EGR valve clogging, and oil leaks from gaskets. These are documented in Fiat service literature and observed in historic vehicle inspections. Adhering to 12,000 km belt replacement and using ethanol-resistant carburettor parts can mitigate many concerns.
The A5.000 was used exclusively in the Fiat 138 range from 1980 to 1984. It powered the 138 (1.5L, 1.5 CL), 138 S, and Panorama estate models. No other Fiat platforms used this engine, and it was not licensed to other manufacturers.
Yes, within mechanical limits. The 138 S variant already features a high-output tune with Weber 34 DMTR carburettor for 64 kW output. Enthusiasts often upgrade to performance camshafts, high-flow heads, and electronic ignition. However, tuning should preserve the engine's balance and avoid over-revving, as the crankshaft and rods are not designed for extreme RPM.
Moderate by modern standards. In a Fiat 138 1.5L, fuel consumption averages ~9.8 L/100km (city) and ~6.9 L/100km (highway), or approximately 29 mpg UK combined. The 138 S model, with higher compression and twin carburettors, may consume 10–15% more fuel under spirited driving.
No. The A5.000 uses a non-interference valve train design. If the timing belt fails or skips, the pistons will not contact the valves, preventing catastrophic internal damage. However, immediate repair is still advised to avoid secondary issues like misfires or poor compression.
Fiat specifies SAE 10W-40 mineral oil meeting API SE/CC standards. This viscosity protects the flat-tappet camshaft and solid lifters effectively. Synthetic oils are not recommended unless seals are upgraded, as they may increase seepage in older gaskets. Oil should be changed every 12,000 km or annually.
Comprehensive technical documentation and regulatory references
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
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