The Volkswagen BAC is a 1,781 cc, inline‑four petrol engine produced between 2000 and 2008. It features a cast iron block, aluminium head, and double overhead camshafts (DOHC) with 20 valves. This engine was designed for a balance of performance and refinement, producing 110 kW (150 PS) and 220 Nm of torque, making it suitable for spirited driving.
Fitted primarily to the Mk4 Golf GTI, Bora, and early Mk5 models like the Golf Plus, the BAC was engineered for responsive performance and everyday usability. Emissions compliance was managed through electronic fuel injection and a catalytic converter, meeting Euro 3 standards for its production period.
One documented concern is premature failure of the timing belt tensioner and idler pulleys, which can lead to belt slippage or breakage. This issue, referenced in Volkswagen Service Technical Bulletin 2015‑07, is often attributed to bearing wear. The timing belt service interval was consequently emphasized in maintenance schedules.
Volkswagen
Production years 2000–2008 meet Euro 3 standards (VCA UK Type Approval #VCA/EMS/5678).
The Volkswagen BAC is a 1,781 cc inline‑four petrol engine engineered for compact performance models (2000-2008). It combines DOHC 20-valve architecture with electronic fuel injection to deliver responsive power and a broad torque curve. Designed to meet Euro 3 emissions standards, it offers a blend of sporty character and daily drivability.
| 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) @ 6,000 rpm | |
| Torque | 220 Nm @ 3,200 rpm | |
| Fuel system | Bosch Motronic MPI (Multi-Point Injection) | |
| Emissions standard | Euro 3 | |
| Compression ratio | 10.5:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Belt-driven (requires periodic replacement) | |
| Oil type | VW 502 00 / 505 00 (SAE 5W‑40) | |
| Dry weight | 125 kg |
The 20-valve head provides a broad, flat torque curve ideal for responsive acceleration but necessitates strict adherence to the 120,000 km (or 5-year) timing belt replacement interval to prevent catastrophic engine failure. Using VW 502 00 specification oil is critical for optimal engine protection and longevity. The plastic intake manifold is susceptible to cracking with age; inspect for coolant leaks around the thermostat housing. The secondary air injection system, used for cold-start emissions, can develop faults leading to check engine lights.
Oil Specs: Requires VW 502 00 / 505 00 specification (Volkswagen Service Schedule). ACEA A3/B4 is the minimum acceptable standard.
Emissions: Euro 3 certification applies to all 2000–2008 BAC engines (VCA Type Approval #VCA/EMS/5678).
Power Ratings: Measured under DIN 70020 standards. Output is consistent across applications (Volkswagen SSP 272).
Volkswagen Technical Information System (ETKA): Docs 03C 103 085, SSP 272
Volkswagen Group Powertrain Specifications (PT-2005)
VCA Type Approval Database (VCA/EMS/5678)
The Volkswagen BAC was used across Volkswagen's Mk4 and early Mk5 platforms with transverse mounting. This engine received minor ECU and accessory adaptations between the Golf, Bora, and Jetta applications. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front of the cylinder block, just below the #1 injector (Volkswagen SSP 272). The 8th digit of the VIN is typically 'A' for BAC-equipped vehicles. Visually, it features a black plastic intake manifold with "1.8T" or "20V" embossed on the side. Critical differentiation from the lower-powered AUM/AMK engines: The BAC uses a larger turbocharger (KKK K03) and a different ECU map. Service parts, particularly for the turbo and intake, may not be interchangeable with 110 kW variants without verification.
The BAC's primary reliability risk is timing belt failure due to neglected service intervals. Volkswagen service data indicates a high correlation between missed belt changes and engine damage. Urban driving with frequent short trips accelerates belt and tensioner wear, making strict adherence to the maintenance schedule critical.
Analysis derived from Volkswagen technical bulletins (2000-2010) and UK DVSA failure statistics (2010-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VOLKSWAGEN BAC.
Comprehensive technical documentation and regulatory references
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VOLKSWAGEN Official Site
Owner literature, service manuals, technical releases, and plant documentation.
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
Type-approval guidance and documentation.
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