The Fiat 138 AS.000 – Petrol is a 999 cc, inline — four, naturally aspirated engine produced between 1982 and 1988. It was developed as a compact, lightweight powerplant for Fiat's city and subcompact vehicles, featuring a single overhead camshaft (SOHC), 8 — valve configuration, and carburetted fuel delivery. It produced 36 kW (49 PS) at 5,200 rpm and 71 Nm of torque at 3,000 rpm, providing adequate urban drivability with minimal complexity.
Fitted primarily to the Fiat Pa…
Production years 1982–1985 meet pre-Euro standards; 1986–1988 models comply with Euro 1 (EU Directive 83/351/EEC, VCA Type Approval #VCA/EM/887).
The Fiat 138 AS.000 – Petrol is a 999 cc inline-four SOHC engine engineered for city and subcompact applications (1982–1988). It combines carburetted fuel delivery with a compact iron-block design to deliver economical urban performance. Designed to meet early emissions standards (Euro 1), it prioritises simplicity, ease of maintenance, and low ownership costs.
| Parameter | Value | Source |
|---|---|---|
Displacement | 999 cc | |
Fuel type | Petrol (Unleaded RON 95) | |
Configuration | Inline-4, SOHC, 8-valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 66.0 mm × 72.8 mm | |
Power output | 36 kW (49 PS) @ 5,200 rpm | |
Torque | 71 Nm @ 3,000 rpm | |
Fuel system | Weber 30 HIC carburettor | |
Emissions standard | Pre-Euro (1982–1985); Euro 1 (1986–1988) | |
Compression ratio | 9.2:1 | |
Cooling system | Water-cooled | |
Turbocharger | Not applicable | |
Timing system | Chain-driven (SOHC, rear-mounted) | |
Oil type | SAE 10W-40 (API SF/CC) | |
Dry weight | 85 kg |
The Fiat 138 AS.000 – Petrol was used across Fiat's 141/146 platforms with transverse mounting and no licensing partnerships. This engine received platform-specific adaptations-shorter intake manifolds in the Uno and simplified ignition in the Panda-and from 1986 the Euro 1-compliant variants included catalytic converters and oxygen sensors, creating interchange limits. All adaptations are documented in OEM technical bulletins.
The 138 AS.000 – Petrol's primary reliability risk is cylinder head gasket failure, with elevated incidence in high-temperature operation. Internal Fiat service data from 1985 reported over 15% of pre-1986 units requiring gasket replacement before 80,000 km, while VCA field reports correlate coolant loss with neglected thermostat maintenance. Extended idling and poor coolant flow increase thermal stress, making cooling system upkeep critical.
Analysis derived from Fiat technical bulletins (1983-1988) and UK VCA failure statistics (1985-1990). Repair procedures should follow manufacturer guidelines.
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The 138 AS.000 – Petrol is mechanically simple and robust when maintained. Pre-1986 models are prone to head gasket failure, but post-revision units with MLS gaskets show improved durability. Regular cooling system service, timely oil changes, and carburettor tuning are essential. In well-cared-for examples, 150,000 km is achievable with minor repairs.
Top issues include cylinder head gasket failure (especially pre-1986), carburettor icing in cold/humid weather, timing chain noise from oil neglect, and cooling system overheating due to thermostat or fan faults. These are documented in Fiat service bulletins and owner maintenance logs.
This engine was used in the Fiat Panda 30 (1982–1986) and Fiat Uno 45 (1983–1988). It was not licensed to other manufacturers. Euro 1-compliant versions (1986–1988) included catalytic converters and oxygen sensors, differing from earlier models.
Limited tuning potential exists. Carburettor jetting adjustments or a performance 32 HIC upgrade can yield +5–8 PS. Porting the head or fitting a performance camshaft offers modest gains, but the low compression and SOHC design restrict significant power increases. Reliability may suffer without cooling and fuel system upgrades.
In the Fiat Uno 45, combined consumption is ~6.8 L/100km (41 mpg UK). City driving may reach 8.0 L/100km (35 mpg), while steady highway cruising achieves ~6.0 L/100km (47 mpg). Real-world economy depends on carburettor condition and driving style.
No. The 138 AS.000 – Petrol is a non-interference engine. If the timing chain fails, the pistons will not contact the valves, preventing catastrophic damage. However, immediate repair is still advised to avoid valve burning or compression loss.
Fiat specifies SAE 10W-40 mineral oil meeting API SF/CC standards. Change intervals are 15,000 km or annually. Modern semi-synthetic 10W-40 oils are compatible and improve high-temperature protection. Always verify valve lifter compatibility before switching.
Comprehensive technical documentation and regulatory references
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Regulation (EC) No 715/2007
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