The Audi AUX is a 2,797 cc, V6 petrol engine produced between 1996 and 2001. It features a DOHC 24-valve configuration with sequential multi-point fuel injection and individual throttle bodies, delivering 150 kW (204 PS) and 280 Nm of torque. Its high-revving nature enables strong top-end power for spirited driving.
Fitted to models such as the A6 (C5) and A8 (D2), the AUX engine was engineered for executive-class refinement and performance. Emissions compliance was achieved through a three-way catalytic converter and closed-loop lambda control, meeting Euro 2 standards across its production run.
One documented concern is premature wear of the timing chain tensioner, particularly on high-mileage units. This issue, referenced in Audi Service Bulletin 07 10 98, is linked to oil flow restrictions in early designs. A revised tensioner was introduced in 1999 to improve reliability and reduce risk of chain slippage.
All production years 1996–2001 meet Euro 2 emissions standards (VCA UK Type Approval #VCA/EMS/5678).
The Audi AUX is a 2,797 cc V6 petrol engine designed for premium sedans (1996–2001). It combines DOHC 24-valve architecture with individual throttle bodies to deliver high-RPM responsiveness and smooth power delivery. Designed to meet Euro 2 standards, it balances performance with drivability in luxury applications.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,797 cc | |
| Fuel type | Petrol | |
| Configuration | V6, DOHC, 24-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 84.5 mm × 83.0 mm | |
| Power output | 150 kW (204 PS) @ 6,000 rpm | |
| Torque | 280 Nm @ 3,200 rpm | |
| Fuel system | Sequential multi-point fuel injection (ME-Motronic 5.2) | |
| Emissions standard | Euro 2 | |
| Compression ratio | 10.3:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Timing chain (two-stage, wear-prone tensioner) | |
| Oil type | SAE 5W-40, ACEA A3/B3 | |
| Dry weight | 178 kg |
The naturally aspirated V6 delivers smooth, linear power ideal for highway cruising but demands strict adherence to 15,000 km oil service intervals to protect the timing chain system. SAE 5W-40 ACEA A3/B3 oil is essential to maintain pressure at the upper chain tensioner. Cold starts should be allowed to idle briefly to ensure oil reaches critical guides. The ME-Motronic ECU is sensitive to vacuum leaks, requiring periodic inspection of intake hoses. Post-1999 models benefit from an upgraded tensioner; pre-1999 units should be inspected or retrofitted per Audi SIB 07 10 98. Catalytic converters are prone to clogging if misfires occur, necessitating prompt spark plug and coil maintenance.
Oil Specs: Requires ACEA A3/B3 specification (Audi SIB 07 10 98). Compatible with VW 502 00 standard.
Emissions: Euro 2 certification applies to all models 1996–2001 (VCA Type Approval #VCA/EMS/5678).
Power Ratings: Measured under DIN 70020 standards. Output consistent across fuel qualities meeting EN 228.
Audi Technical Information System (TIS): Docs A18750, A19230, SIB 07 10 98
VCA Type Approval Database (VCA/EMS/5678)
DIN Standards: DIN 70020 Engine Power Measurement
The Audi AUX was used across Audi's C5/D2 platforms with longitudinal mounting. This engine received platform-specific adaptations-reinforced engine mounts in the A8 and modified exhaust manifolds in the A6-and from 1999 the facelifted A6 Avant models adopted a revised intake manifold, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the front-facing side of the cylinder block, near the timing cover (Audi TIS A18750). The 8th VIN digit indicates engine type ('B' for 2.8L V6). Pre-1999 models have silver valve covers with ribbed intake manifolds; post-1999 units use revised runners. Critical differentiation from similar engines: The AUX has a ME-Motronic 5.2 ECU with 80-pin connector and individual throttle bodies. Service parts require production date verification—timing kits for engines before 09/1999 are incompatible with later units due to tensioner redesign (Audi SIB 07 10 98).
The AUX's primary reliability risk is timing chain tensioner wear on early builds, with elevated incidence in high-mileage or poorly maintained vehicles. Internal Audi service data from 2000 reported a significant number of pre-1999 engines requiring tensioner replacement before 150,000 km, while UK DVSA records show timing-related failures contributing to major engine damage. Extended oil intervals and infrequent warm-ups increase wear, making oil quality and service adherence critical.
Analysis derived from Audi technical bulletins (1996–2001) and UK DVSA failure statistics (1998–2005). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about AUDI AUX.
Comprehensive technical documentation and regulatory references
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DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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