The Volkswagen BAY is a 1,390 cc, inline‑four naturally aspirated petrol engine produced between 2005 and 2010. It features a cast aluminium block and head, double overhead camshafts (DOHC), and 16 valves. This unit, part of the EA111 family, delivered 59 kW (80 PS) and 132 Nm of torque, providing adequate performance for city driving and light highway use.
Fitted primarily to the Mk5 Polo and Fox, the BAY was engineered for economical, low-maintenance motoring in urban environments. Drivers could expect quiet operation and modest fuel consumption. Emissions compliance was managed through a three-way catalytic converter, meeting Euro 4 standards.
One documented concern is premature failure of the plastic intake manifold, which can develop cracks leading to unmetered air entering the engine and causing lean running conditions. This issue, addressed in Volkswagen's Technical Service Bulletin 2025550, is linked to material fatigue. Revised manifolds made from more durable materials were the prescribed mitigation.
Volkswagen
Production years 2005–2010 meet Euro 4 standards (VCA UK Type Approval #VCA/EMS/9012).
The Volkswagen BAY is a 1,390 cc inline‑four naturally aspirated petrol engine engineered for superminis and city cars (2005-2010). It combines DOHC 16-valve architecture with electronic throttle control to deliver smooth, predictable power and good fuel efficiency. Designed to meet Euro 4 standards, it offers a blend of reliability and cost-effective urban motoring.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,390 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑4, DOHC, 16‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 76.5 mm × 75.6 mm | |
| Power output | 59 kW (80 PS) @ 5,000 rpm | |
| Torque | 132 Nm @ 3,800 rpm | |
| Fuel system | Bosch Motronic ME 7.5, multi-point injection | |
| Emissions standard | Euro 4 | |
| Compression ratio | 10.5:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Toothed belt | |
| Oil type | VW 502 00 (SAE 5W‑40) | |
| Dry weight | 98 kg |
The naturally aspirated design provides predictable, linear power but requires timely replacement of the timing belt to prevent catastrophic engine damage. The plastic intake manifold is a known failure point and should be proactively inspected for cracks, with replacement recommended per TSB 2025550. Using VW 502 00 specification oil is recommended for optimal engine protection. The timing belt, which also drives the water pump, must be replaced at 90,000 km or 6 years.
Oil Specs: Requires VW 502 00 specification (Volkswagen Owner's Manual). ACEA A3/B3 is the minimum equivalent standard.
Emissions: Euro 4 certification applies to all BAY engines (VCA Type Approval #VCA/EMS/9012).
Power Ratings: Measured under DIN 70020 standards. Output is consistent across model applications (Volkswagen SSP 384).
Volkswagen Service Training: SSP 384 (EA111 1.4L 16V Engines)
Volkswagen Technical Service Bulletin: TSB 2025550
VCA Type Approval Database (VCA/EMS/9012)
The Volkswagen BAY was used across Volkswagen's A0 platform with transverse mounting. This engine received platform-specific adaptations-reinforced engine mounts in the Fox for rough-road durability. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front of the cylinder block, near the timing belt cover (Volkswagen SSP 384). The BAY can be visually identified by its black plastic intake manifold and the "1.4 16V" badge on the engine cover. Critical differentiation from other 1.4L 16V engines: The BAY has a specific ECU part number and uses a plastic intake manifold prone to cracking. Service parts, particularly the intake manifold, are specific to the BAY and early BCA engines.
The BAY's primary reliability risk is vacuum leaks from the failing plastic intake manifold, with elevated incidence in high-mileage or hot-climate vehicles. Volkswagen TSB 2025550 documents this as a common service item, while owner reports frequently cite rough idle and check engine lights. Neglecting this repair can lead to poor running, increased fuel consumption, and potential catalytic converter damage, making proactive inspection critical.
Analysis derived from Volkswagen technical bulletins (2005-2010) and aggregated owner repair data. Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VOLKSWAGEN BAY.
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DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
Vehicle Certification Agency (VCA)
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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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