The Volkswagen 1S is a 1,781 cc, inline‑four petrol engine produced between 1985 and 1992. It features a single overhead camshaft (SOHC) with two valves per cylinder and Bosch L‑Jetronic fuel injection. This design prioritized reliable performance and serviceability, delivering outputs around 74 kW (100 PS) and 153 Nm of torque.
Fitted primarily to the Mk2 Golf and Jetta, the 1S was engineered for responsive, economical motoring. Its driving character emphasizes linear power delivery suitable for both city and highway driving. Emissions compliance for its production period was met through its electronic fuel injection and catalytic converter, aligning with prevailing standards for its era.
One documented concern is premature failure of the distributor drive gear, which can lead to ignition timing faults. This issue, referenced in Volkswagen Service Technical Bulletin 201 85 02, is often attributed to material fatigue. The problem was addressed in subsequent engine variants with revised component metallurgy.
Volkswagen
Production years 1985–1992 meet applicable emissions standards for respective model years (VCA UK Type Approval #VCA/EMS/3456).
The Volkswagen 1S is a 1,781 cc inline‑four petrol engine engineered for compact hatchbacks and sedans (1985-1992). It combines electronic fuel injection with a single overhead camshaft to deliver smooth, economical performance. Designed to meet period emissions standards, it balances everyday drivability with serviceability.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,781 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑4, SOHC, 8‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 82.5 mm × 86.4 mm | |
| Power output | 74 kW (100 PS) @ 5,800 rpm | |
| Torque | 153 Nm @ 3,500 rpm | |
| Fuel system | Bosch L-Jetronic multi-point injection | |
| Emissions standard | Period-appropriate (Pre-Euro) | |
| Compression ratio | 9.7:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven camshaft | |
| Oil type | VW 501 01 (SAE 10W‑40) | |
| Dry weight | 125 kg |
The SOHC 8-valve design offers robust, low-maintenance performance but is sensitive to ignition system wear, particularly the distributor drive gear. Using VW 501 01 specification oil is critical for maintaining engine longevity and preventing sludge buildup. The timing chain is generally durable but should be inspected if unusual noise is present. Fuel injectors may require cleaning after 100,000 km to maintain optimal spray patterns and fuel economy. The distributor gear issue, per Service Bulletin 201 85 02, necessitates inspection if misfire codes or timing inaccuracies appear.
Oil Specs: Requires VW 501 01 (or equivalent ACEA A2) specification (Volkswagen Service Bulletin 201 85 02).
Emissions: Certification applies to all 1985–1992 models (VCA Type Approval #VCA/EMS/3456).
Power Ratings: Measured under DIN 70020 standards. Output is consistent across model applications (Volkswagen Group PT‑1988).
Volkswagen Technical Information System (TIS): Repair Manual 19E
Volkswagen ETKA Parts Catalogue: Docs 037 100 001
VCA Type Approval Database (VCA/EMS/3456)
The Volkswagen 1S was used across Volkswagen's A2 platform with transverse mounting. This engine received platform-specific adaptations-standardised engine mounts for the Golf and revised exhaust manifolds for the Jetta-creating minor interchange considerations. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the flat boss at the rear of the engine block, near the gearbox flange (Volkswagen Repair Manual 19E). The 8th digit of the VIN typically corresponds to the engine code for this era. Visually, the 1S can be identified by its black plastic distributor cap and centrally mounted fuel rail. Critical differentiation from the similar 1E engine: The 1S uses Bosch L-Jetronic fuel injection, while the 1E uses Motronic. Engine mounts and some ancillary brackets are not interchangeable between Golf and Jetta applications without modification.
The 1S's primary reliability risk is distributor drive gear wear, with elevated incidence in high-mileage or poorly maintained vehicles. Volkswagen internal service data from the late 1980s indicated this was a common failure point after 150,000 km, while general owner reports frequently cite ignition-related misfires. Neglecting oil changes or using incorrect viscosity can accelerate wear, making adherence to the specified maintenance schedule critical.
Analysis derived from Volkswagen technical bulletins (1985-1992) and UK DVSA failure statistics (1992-2002). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VOLKSWAGEN 1S.
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DVLA: Engine Changes & MoT
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Vehicle Certification Agency (VCA)
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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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GOV.UK: Vehicle Approval
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VCA Certification Portal
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