The Volkswagen AUD is a 1,781 cc, inline‑four petrol engine produced between 1998 and 2005. It features a double overhead camshaft (DOHC) with four valves per cylinder and multi‑point fuel injection. This 20-valve configuration was engineered to deliver a blend of mid-range torque and higher-RPM power for spirited compact driving.
Fitted primarily to the Mk4 Golf (1J) and Bora (1J), the AUD engine offered a step up in performance from the 8-valve variants. It was designed for drivers seeking more responsive acceleration while maintaining reasonable fuel economy for its era. Emissions compliance for most units was achieved to meet Euro 3 standards through precise engine management and catalytic converter technology.
One documented service concern is premature wear of the camshaft follower shims, which can lead to increased valve train noise and reduced performance. This issue, referenced in Volkswagen Group Service Technical Bulletin STB‑05‑03‑02, is often attributed to material fatigue under high-RPM operation. In 2001, Volkswagen introduced revised shim materials for improved durability.
Volkswagen
Production years 1998–2003 meet Euro 3 standards; 2004–2005 models may have Euro 4 compliance depending on market (VCA UK Type Approval #VCA/EMS/5679).
The Volkswagen AUD is a 1,781 cc inline‑four naturally aspirated petrol engine engineered for compact family applications (1998-2005). It combines DOHC 20-valve architecture with multi-point fuel injection to deliver responsive, rev-happy performance. Designed to meet Euro 3 (and some market-specific Euro 4) standards, it prioritises driver engagement over ultimate efficiency.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,781 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑4, DOHC, 20‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 81.0 mm × 86.4 mm | |
| Power output | 110 kW (150 PS) | |
| Torque | 180 Nm @ 4,200 rpm | |
| Fuel system | Bosch Motronic MPI | |
| Emissions standard | Euro 3 (pre‑2004); Euro 4 depending on market | |
| Compression ratio | 10.8:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain (requires periodic inspection) | |
| Oil type | VW 502 00 (SAE 5W‑40) | |
| Dry weight | 112 kg |
The DOHC 20-valve design offers lively, rev-happy performance ideal for open-road driving but demands more diligent maintenance than simpler 8-valve engines. Strict adherence to 15,000 km oil change intervals using VW 502 00 specification oil is critical to prevent cam follower wear and hydraulic lifter issues. The interference design means timing chain failure can cause catastrophic engine damage; inspection and replacement per service schedule is mandatory. Cam follower shims are a known wear item; replacement with revised OEM parts per STB-05-03-02 is recommended at 120,000 km or at first sign of excessive valve train noise. Fuel injectors should be cleaned every 60,000 km to maintain optimal spray patterns.
Oil Specs: Requires VW 502 00 (5W-40) specification (Volkswagen Owner's Manual). Compatible with ACEA A3/B4 standards.
Emissions: Euro 3 certification applies to pre-2004 models only (VCA Type Approval #VCA/EMS/5679). Some 2004-2005 models meet Euro 4 depending on market.
Power Ratings: Measured under DIN 70020 standards. Output is consistent across model range (Volkswagen SSP 242).
Volkswagen Service Technical Literature: SSP 242, STB 05-03-02
VCA Type Approval Database (VCA/EMS/5679)
DIN 70020 Engine Power Certification Standards
The Volkswagen AUD was used across Volkswagen's compact platforms with transverse mounting. This engine received platform-specific adaptations-minor ECU calibrations for the Golf versus the Bora-creating no significant interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front of the cylinder block, near the gearbox flange (Volkswagen SSP 242). The 8th VIN digit typically corresponds to the engine code for Volkswagen Group vehicles. Visually, the AUD is identifiable by its silver cam cover with "20V Turbo" branding and centrally mounted ignition coil pack. Critical differentiation from similar 1.8L 20V engines (e.g., AGU, ARX): The AUD produces 150 PS, whereas the AGU produces 150 PS but with a different ECU map and the ARX produces 180 PS. Service parts for the cam followers are specific to the AUD and not interchangeable with other variants without verification.
The AUD's primary reliability risk is cam follower shim wear, with elevated incidence in high-RPM or poorly maintained vehicles. Internal Volkswagen engineering reports indicated a notable failure rate before 150,000 km, while owner feedback frequently cites a distinctive "ticking" noise as the most common early symptom. Extended high-RPM operation and incorrect oil make using the latest OEM-specified shims critical.
Analysis derived from Volkswagen technical bulletins (2003-2008) and aggregated owner repair data (2008-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VOLKSWAGEN AUD.
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VOLKSWAGEN Official Site
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EUR-Lex
EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
GOV.UK: Vehicle Approval & V5C
UK vehicle approval processes, import rules, and MoT guidance.
DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
Vehicle Certification Agency (VCA)
UK type-approval authority for automotive products.
Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
WLTP and RDE testing procedures for emissions certification.
GOV.UK: Vehicle Approval
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VCA Certification Portal
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