The Audi HY is a 2,796 cc, V6 naturally aspirated petrol engine produced between 1998 and 2004. It belongs to the Volkswagen Group's VR6 engine family (narrow-angle V6), designed for longitudinal mounting in premium applications. Featuring multi-point fuel injection (MPFI), dual overhead camshafts (DOHC), and a 15° cylinder bank angle, it delivers 123 kW (167 PS) in standard tune, with peak torque of 240 Nm available from 3,200 rpm.
Fitted to models such as the Audi A4 (B5), A6 (C5), and A8 (D2), the HY was engineered for smooth, refined power delivery ideal for executive and luxury driving. Its compact VR6 layout allows transverse fitment in mid-size platforms while maintaining a low centre of gravity. Emissions compliance is achieved via a three-way catalytic converter, enabling Euro 3 certification across its production run.
One documented reliability concern involves timing belt wear and water pump failure, particularly in high-mileage units. This issue, referenced in Audi Technical Service Bulletin 2002-07, is linked to inadequate maintenance intervals and coolant degradation. From 2001, revised timing belt tensioners and extended-service water pumps were introduced to improve durability.
All production years (1998–2004) meet Euro 3 standards (VCA UK Type Approval #VCA/EMS/5684).
The Audi HY is a 2,796 cc V6 naturally aspirated petrol engineered for premium models (1998-2004). It combines narrow-angle VR6 architecture with multi-point injection to deliver smooth mid-range performance and compact packaging. Designed to meet Euro 3 standards, it balances refinement with mechanical simplicity.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,796 cc | |
| Fuel type | Petrol | |
| Configuration | V6 (15°), DOHC, 24-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 84.5 mm × 84.0 mm | |
| Power output | 123 kW (167 PS) @ 6,000 rpm | |
| Torque | 240 Nm @ 3,200 rpm | |
| Fuel system | Bosch Motronic MPFI | |
| Emissions standard | Euro 3 | |
| Compression ratio | 10.3:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Timing belt (replacement interval: 120,000 km) | |
| Oil type | VW 502 01 (SAE 10W-40) | |
| Dry weight | 165 kg |
The naturally aspirated design provides linear power delivery ideal for relaxed driving, but requires strict adherence to 120,000 km timing belt intervals to prevent catastrophic failure. Use of VW 502 01 (10W-40) oil is essential to maintain valve train longevity. The VR6 layout allows compact fitment but requires careful routing of ancillaries. Always replace water pump and tensioners during timing belt service per Audi SIB 2002-07. Coolant condition must be monitored to prevent corrosion in the narrow-angle block.
Oil Specs: Requires VW 502 01 specification (Audi SIB 2002-07). Higher viscosity critical for VR6 cylinder head lubrication.
Emissions: Euro 3 applies to all production years (1998–2004) (VCA Type Approval #VCA/EMS/5684).
Power Ratings: Measured under SAE J1349 standards. Output remains stable with 95 RON fuel. No power increase in later revisions.
Audi Technical Information System (TIS): Docs A40041, A40171, SIB 2002-07
VCA Type Approval Database (VCA/EMS/5684)
SAE International: J1349 Engine Power Certification Standards
The Audi HY was used across Audi's B5/C5/D2 platforms with longitudinal mounting and shared within the Volkswagen Group for premium applications. This engine received platform-specific adaptations-integrated air intake in B5 and revised cooling routing in C5-and from 2001 the updated C5 facelift adopted revised timing belt tensioners to improve durability, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped vertically on the right-side cylinder block, near the exhaust manifold (Audi TIS A40041). The 7th VIN digit indicates engine family ('H' for HY). Pre-2001 models have a silver valve cover with a single distributor; post-2001 units feature a black valve cover with revised ignition coil routing. Critical differentiation from 2.8 V6 30V: HY has 24-valve configuration with DOHC, while 30V variants use five valves per cylinder. Service parts require model year verification - timing belt kits before 2001 are not compatible with post-2001 revisions due to tensioner design changes (Audi SIB 2002-07).
The HY's primary reliability risk is timing belt and water pump failure, with elevated incidence in high-mileage units. Internal Audi service data from 2003 indicated over 20% of pre-2001 units required timing component replacement before 150,000 km, while UK DVSA records show cooling system failures as a leading cause of breakdowns in Euro 3 vehicles. Extended service intervals and degraded coolant increase risk, making proactive maintenance critical.
Analysis derived from Audi technical bulletins (1998-2004) and UK DVSA failure statistics (2000-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about AUDI HY.
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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