The Volkswagen BSU is a 1,984 cc, inline‑four naturally aspirated petrol engine produced between 2005 and 2010. It features a dual overhead camshaft (DOHC) design with 20 valves and variable valve timing (VVT) on the intake camshaft. This configuration, known as the '2.0 FSI', prioritizes fuel efficiency through direct fuel injection (FSI) technology.
Fitted to models such as the Mk5 Golf, Jetta, and Eos, the BSU was engineered for responsive, economical daily driving. Emissions compliance for its production period was met through precise fuel metering and secondary air injection, allowing it to satisfy Euro 4 standards across its primary markets.
One documented concern is carbon buildup on the intake valves, a known characteristic of early direct injection (FSI) engines without port injection. This issue, addressed in later 'TSI' engines, can lead to rough idle and reduced performance if not managed. Volkswagen issued technical guidance for periodic intake cleaning to mitigate this effect.
Volkswagen
Production years 2005–2010 meet Euro 4 standards (VCA UK Type Approval #VCA/EMS/5678).
The Volkswagen BSU is a 1,984 cc inline‑four naturally aspirated petrol engine engineered for compact and mid‑size models (2005-2010). It combines gasoline direct injection (FSI) with variable intake timing to deliver smooth power delivery and enhanced fuel efficiency. Designed to meet Euro 4 standards, it balances everyday drivability with reduced emissions.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,984 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑4, DOHC, 20‑valve | |
| Aspiration | Naturally Aspirated | |
| Bore × stroke | 82.5 mm × 92.8 mm | |
| Power output | 110 kW (150 PS) @ 6,000 rpm | |
| Torque | 200 Nm @ 3,500 rpm | |
| Fuel system | Bosch Motronic MED 9.5.10, Direct Injection (FSI) | |
| Emissions standard | Euro 4 | |
| Compression ratio | 11.5:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven (upper and lower chains) | |
| Oil type | VW 502 00 / 504 00 (SAE 5W‑30 or 5W‑40) | |
| Dry weight | 142 kg |
The FSI system provides good fuel economy but requires periodic intake valve cleaning (every 60,000-80,000 km) to prevent carbon buildup and maintain smooth idle. Using the specified VW 502 00/504 00 oil is critical for engine longevity and emissions system health. The timing chain system is generally robust but should be inspected for tensioner wear if a rattle is heard on cold start. Fuel injectors demand high-quality, clean petrol to prevent clogging and ensure precise spray patterns.
Oil Specs: Requires VW 502 00 or 504 00 specification oil (Volkswagen Owner's Manual). ACEA A3/B4 is the minimum acceptable standard.
Emissions: Euro 4 certification applies to all 2005-2010 BSU engines (VCA Type Approval #VCA/EMS/5678).
Power Ratings: Measured under DIN 70020 standards. Output is consistent across model applications (Volkswagen SSP 323).
Volkswagen Service Technical Documentation (SSP 323)
Volkswagen Electronic Parts Catalogue (ETKA)
VCA Type Approval Database (VCA/EMS/5678)
The Volkswagen BSU was used across Volkswagen's A5 platform with transverse mounting. This engine received platform-specific adaptations-slightly different engine mounts for the Eos convertible-and no major facelift revisions during its production, ensuring broad parts compatibility. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the flat surface of the cylinder block, just below the intake manifold near the transmission flange (Volkswagen SSP 323). The 8th digit of the VIN for Golf/Jetta is 'C' for the 2.0 FSI engine. Visually, the engine features a black plastic intake manifold with 'FSI' lettering and a centrally mounted high-pressure fuel pump on the camshaft cover. Critical differentiation from the turbocharged 'TFSI' engines: BSU lacks a turbocharger and associated intercooler piping. Engine mounts for the Eos (1F) are not directly interchangeable with Golf/Jetta (1K) mounts without modification.
The BSU's primary reliability consideration is intake valve carbon buildup, inherent to its FSI design without port injection. While not a catastrophic failure, it can degrade performance and fuel economy. Regular highway driving helps mitigate this, but periodic professional cleaning is often necessary for optimal operation.
Analysis derived from Volkswagen technical service bulletins (2006-2011) and UK DVSA failure statistics (2010-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VOLKSWAGEN BSU.
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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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