The Volkswagen JK is a 1,781 cc, inline‑four naturally aspirated petrol engine produced between 1986 and 1991. It features a single overhead camshaft (SOHC), 8‑valve cylinder head, and Bosch KE‑Jetronic continuous fuel injection. In standard form it delivered 70 kW (95 PS) at 5,400 rpm with 148 Nm of torque at 3,500 rpm, offering improved throttle response over earlier L‑Jetronic variants.
Fitted to models such as the Mk2 Golf GT, Jetta GL, and Scirocco Base, the JK was engineered for balanced daily driving with modest performance gains over the HK engine. Emissions compliance was achieved through catalytic converter integration and oxygen sensor feedback, meeting Euro 1 standards in all production years.
One documented concern is fuel distributor wear in the KE‑Jetronic system, which can cause lean running and hesitation. This issue, referenced in Volkswagen Service Bulletin 01‑90‑12, stems from internal plunger scoring due to fuel contamination or moisture ingress. From 1989 onward, revised distributor seals and fuel filter specifications were introduced to mitigate failure rates.
All production years (1986–1991) meet Euro 1 emissions standards (VCA UK Type Approval #VCA/EMS/5678).
The Volkswagen JK is a 1,781 cc inline‑four naturally aspirated petrol engine engineered for compact hatchbacks and sedans (1986–1991). It combines Bosch KE‑Jetronic continuous injection with a SOHC 8‑valve layout to deliver smoother idle and improved throttle linearity over predecessor L‑Jetronic systems. Designed to meet Euro 1, it balances drivability with serviceability.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,781 cc | |
| Fuel type | Petrol (Unleaded) | |
| Configuration | Inline‑4, SOHC, 8‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 81.0 mm × 86.4 mm | |
| Power output | 70 kW (95 PS) @ 5,400 rpm | |
| Torque | 148 Nm @ 3,500 rpm | |
| Fuel system | Bosch KE‑Jetronic continuous fuel injection | |
| Emissions standard | Euro 1 | |
| Compression ratio | 9.3:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain (front‑mounted) | |
| Oil type | VW 500 00 (SAE 10W‑40 mineral or semi‑synthetic) | |
| Dry weight | 114 kg |
The SOHC 8‑valve layout provides mechanical simplicity but requires valve clearance adjustment every 30,000 km. Bosch KE‑Jetronic systems are sensitive to fuel quality—contaminated or ethanol‑blended fuels accelerate distributor wear. Use of VW 500 00–spec oil is essential for chain tensioner longevity. Catalytic converter integrity depends on consistent lambda control; oxygen sensor failure should be addressed immediately to prevent catalyst damage. Post‑1989 engines feature improved fuel distributor seals per SIB 01‑90‑12.
Oil Specs: Requires VW 500 00 (10W-40) specification (Volkswagen Owner’s Manual Mk2 GT). ACEA A2/B2 oils are acceptable substitutes.
Emissions: Euro 1 certification applies to all 1986–1991 JK engines (VCA Type Approval #VCA/EMS/5678).
Power Ratings: Measured under DIN 70020 standards. Output verified on dynamometer per Volkswagen PT‑1987.
Volkswagen Technical Information System (TIS): Docs V‑1135, V‑1148
VCA Type Approval Database (VCA/EMS/5678)
Volkswagen Service Information Bulletin 01‑90‑12
The Volkswagen JK was used across Volkswagen's Mk2 platforms with transverse mounting and no external licensing. This engine received platform-specific adaptations—reinforced intake manifolds in the Golf GT and modified exhaust routing in the Jetta—and from 1989 the introduction of updated fuel distributor seals, creating minor interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front flange of the cylinder block near the transmission bellhousing (Volkswagen TIS V‑1135). The 4th and 5th digits of the VIN (e.g., “19” for Golf Mk2) indicate model, while engine code “JK” appears on the build sticker in the boot lid or service booklet. All JK engines include a catalytic converter and oxygen sensor. Critical differentiation from HK: JK uses KE‑Jetronic with a mechanical fuel distributor and air flow plate, whereas HK uses L‑Jetronic with electronic injectors and airflow meter.
The JK's primary reliability risk is KE‑Jetronic fuel distributor wear, with elevated incidence in vehicles using poor-quality or ethanol-blended fuel. Volkswagen internal service data from 1990 noted increased injector and plunger faults in regions with inconsistent fuel standards, while UK DVSA records show lambda control failures as a recurring MOT emissions issue. Fuel contamination and infrequent filter changes make proactive maintenance critical.
Analysis derived from Volkswagen technical bulletins (1986–1992) and UK DVSA failure statistics (1990–2005). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VOLKSWAGEN JK.
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Regulation (EC) No 715/2007
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