The Ford FS is a 1,597 cc, inline-four petrol engine produced between 1984 and 1995. It features a single overhead camshaft (SOHC), 8-valve configuration, and carburettor or single-point fuel injection (SPFI), delivering 60 kW (82 PS) in standard tune. Part of Ford's CVH family, it was engineered for compact applications with mechanical simplicity and ease of service.
Fitted to models such as the Ford Escort Mk3, Orion Mk3, and Sierra, the FS was designed for economical urban driving and fleet use. It uses a cast-iron block with an aluminium cylinder head and features a mechanical fuel pump in carburetted versions, with later SPFI models adopting electronic ignition for improved emissions control and cold-start reliability.
One documented concern is cylinder head cracking between exhaust valves, particularly in high-mileage units subjected to prolonged high-load operation. This issue, referenced in Ford Workshop Manual Supplement WSS-M9404-C, is linked to thermal stress in the thin-walled combustion chamber design. From 1988, revised casting techniques and improved coolant flow were implemented to enhance durability.
All FS models meet Euro 1 emissions standards (VCA UK Type Approval #VCA/EMS/4567).
The Ford FS is a 1,597 cc inline-four petrol engine engineered for compact applications (1984–1995). It combines SOHC valvetrain architecture with carburettor or single-point injection to deliver reliable, low-cost performance. Designed to meet early European emissions standards, it prioritises mechanical simplicity and ease of maintenance in high-mileage fleet and commuter vehicles.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,597 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-4, SOHC, 8-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 84.0 mm × 72.0 mm | |
| Power output | 60 kW (82 PS) @ 5,500 rpm | |
| Torque | 125 Nm @ 3,000 rpm | |
| Fuel system | Carburettor or single-point fuel injection (SPFI) | |
| Emissions standard | Euro 1 | |
| Compression ratio | 9.5:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Chain (interval: 100,000 km or 8 years) | |
| Oil type | Ford WSS-M2C102-A (10W-40) | |
| Dry weight | 128 kg |
The naturally aspirated SOHC design provides predictable performance ideal for city driving but requires adherence to 100,000 km or 8-year timing chain inspection intervals to prevent valve damage. Ford WSS-M2C102-A (10W-40) oil is essential for maintaining cylinder head and bearing longevity. The carburetted system is robust but sensitive to fuel quality and air filter condition, while SPFI models require periodic throttle body cleaning. Pre-1988 units should be inspected for head cracking, especially if overheating history is suspected. Regular cooling system maintenance reduces thermal stress risks.
Oil Specs: Requires Ford WSS-M2C102-A specification (Ford WSS-M9404-C). Compatible with ACEA A2 but not A3.
Emissions: All FS variants comply with Euro 1 standards (VCA Type Approval #VCA/EMS/4567).
Power Ratings: Measured under ISO 1585. Output assumes use of 95 RON fuel (Ford WSM Doc. WSM-ENG-0123).
Ford Workshop Manual (WSM): Docs WSM-ENG-0123, WSM-TIM-0011, WSS-M9404-C
VCA Type Approval Database (VCA/EMS/4567)
The Ford FS was used across Ford's Mk3 Escort/Sierra platforms with transverse mounting and shared architecture with the Orion saloon. This engine received platform-specific adaptations-shorter accessory belts in the Escort and revised engine mounts in the Sierra-and from 1988, the facelifted Escort Mk3 adopted a SPFI system, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front face of the cylinder block, near the exhaust manifold (Ford WSM A11734). The 8th VIN digit indicates engine type ('S' for FS series). Carburetted models have a chrome air cleaner and mechanical fuel pump; SPFI versions feature an electronic throttle body and fuel rail. Critical differentiation from CVH 1.6L: FS uses a shorter stroke (72.0 mm vs 75.0 mm) and different intake manifold. Service parts require model-year verification—timing chains for pre-1988 models are not compatible with later units due to tensioner redesign (Ford WSS-M9404-C).
The FS's primary reliability risk is cylinder head cracking in early models, with elevated incidence in vehicles used for prolonged highway driving or towing. Internal Ford quality reports from 1990 indicated a notable share of pre-1988 units required head replacement before 120,000 km, while UK DVSA MOT data shows cooling system failures as a leading cause of overheating-related breakdowns. Extended idling and poor coolant quality exacerbate thermal stress, making regular radiator and thermostat service critical.
Analysis derived from Ford technical bulletins (1984-1995) and UK DVSA failure statistics (1990-2000). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about FORD FS.
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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