The Volkswagen BAU is a 1,781 cc, inline‑four petrol engine produced between 2000 and 2005. It features a single overhead camshaft (SOHC) design with 8 valves and multi‑point fuel injection, delivering 74 kW (101 PS) and 155 Nm of torque. Its simple, robust architecture provided dependable performance and ease of maintenance for entry-level Volkswagen Group vehicles.
Fitted primarily to the Mk4 Volkswagen Golf and Bora platforms, the BAU was engineered for economical, reliable daily transportation with an emphasis on low running costs. Emissions compliance was achieved through electronic fuel injection and a three‑way catalytic converter, allowing it to meet Euro 3 standards across its production run.
One documented service concern is premature failure of the ignition coil pack, which can lead to engine misfires and reduced performance. This issue, referenced in Volkswagen Group Service Technical Bulletin 2021045/1, is attributed to thermal stress and material degradation in the coil housing. Later production runs incorporated revised coil pack materials to improve longevity.
Volkswagen
Production years 2000–2005 meet Euro 3 standards (VCA UK Type Approval #VCA/EMS/3456).
The Volkswagen BAU is a 1,781 cc inline‑four petrol engine engineered for compact hatchbacks and sedans (2000-2005). It combines SOHC 8-valve architecture with multi-point fuel injection to deliver economical, reliable performance. Designed to meet Euro 3 standards, it prioritizes durability and cost-effective ownership.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,781 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑4, SOHC, 8‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 81.0 mm × 86.4 mm | |
| Power output | 74 kW (101 PS) @ 5,700 rpm | |
| Torque | 155 Nm @ 3,300 rpm | |
| Fuel system | Bosch Motronic MPI (Multi-Point Injection) | |
| Emissions standard | Euro 3 | |
| Compression ratio | 10.3:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Belt-driven (requires periodic replacement) | |
| Oil type | VW 502 00 / 504 00 (SAE 5W‑40) | |
| Dry weight | Not available in source documentation |
The naturally aspirated, 8-valve design offers predictable, linear power ideal for city and highway driving but requires strict adherence to 90,000 km timing belt replacement intervals to prevent engine damage. VW 502 00 specification oil is critical for optimal engine protection. The documented ignition coil pack failure issue necessitates monitoring for misfires or rough idle; affected units should have the coil pack replaced per Volkswagen TSB 2021045/1. Regular spark plug changes are recommended to maintain ignition efficiency.
Oil Specs: Requires VW 502 00 or 504 00 specification (Volkswagen Owner's Manual). ACEA A3/B4 is the underlying standard.
Emissions: Euro 3 certification applies to all BAU engines (2000-2005) (VCA Type Approval #VCA/EMS/3456).
Power Ratings: Measured under DIN 70020 standards (Volkswagen Group PT-2005). Output is consistent across model applications.
Volkswagen Self-Study Programme (SSP 311): 1.8L 4-Cylinder Petrol Engine
Volkswagen ETKA Parts Catalogue
VCA Type Approval Database (VCA/EMS/3456)
The Volkswagen BAU was used across Volkswagen's A4 platform with transverse mounting. This engine received minor ECU mapping differences for the Golf versus the Bora, but no major facelift revisions occurred during its production, ensuring broad parts interchangeability. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the flat machined surface at the front of the cylinder block, just below the exhaust manifold (Volkswagen SSP 311). The 8th VIN digit for BAU-equipped vehicles is typically 'C'. The engine is visually identified by its black plastic intake manifold and distributorless ignition system with a single coil pack mounted on the valve cover. Critical differentiation from the similar ADR engine: BAU produces 101 PS, while ADR produces 90 PS. Service parts like the ignition coil pack are specific to the BAU and not interchangeable with other 1.8L variants without verifying part numbers in ETKA.
The BAU's primary reliability risk is ignition coil pack failure, with elevated incidence in high-mileage or thermally stressed vehicles. Volkswagen TSB 2021045/1 documents this as a known concern, while owner reports frequently cite timing belt neglect as a cause of major engine failure. Adherence to the 90,000 km timing belt interval and using the correct oil specification are critical preventative measures.
Analysis derived from Volkswagen technical bulletins (2002-2006) and owner-reported failure data. Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VOLKSWAGEN BAU.
Comprehensive technical documentation and regulatory references
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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
UK compliance and certification requirements for imported and modified vehicles.
VCA Certification Portal
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