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 ach…
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 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.
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.
The most common questions about engine codes, what they mean, how to find them and how this database works
The AUX engine is fundamentally robust with good build quality, but early models (1996–1998) are prone to timing chain tensioner failure. Post-1999 revisions significantly improved reliability. With regular maintenance—especially oil changes every 15,000 km using 5W-40 ACEA A3/B3 oil—well-cared-for units can exceed 200,000 km.
The most documented issues are timing chain tensioner wear, intake manifold vacuum leaks, ignition coil failures, and coolant leaks from the thermostat housing. These are confirmed in Audi service bulletins and technical reports. Preventative maintenance greatly reduces the likelihood of major repairs.
The AUX engine was used exclusively in the Audi A6 (C5) and A8 (D2) models from 1996 to 2001, badged as the 2.8. It was not used in other Audi lines or licensed to other manufacturers. All applications are longitudinal, front-engine layouts with quattro or front-wheel drive.
Limited tuning potential exists. ECU remaps can yield +15–20 kW by optimizing throttle response and fueling, but the naturally aspirated design limits gains. Aftermarket performance cams or ported heads can increase output, though these are costly. Reliability remains tied to maintaining the timing system and cooling integrity.
Moderate for its class. In the A6 2.8, combined consumption is approximately 10.5 L/100km (26.9 mpg UK), with city driving around 13.0 L/100km and highway as low as 8.5 L/100km. Driving style significantly affects economy due to the engine's high-revving nature and throttle sensitivity.
Yes. The AUX is an interference engine, meaning a timing chain failure can result in piston-to-valve contact and severe internal damage. Immediate attention to any startup rattle or timing fault codes is essential to prevent catastrophic engine failure.
Audi specifies SAE 5W-40 oil meeting ACEA A3/B3 standards. Use of VW 502 00-compliant oil is acceptable. Oil changes every 15,000 km or annually are critical to maintain oil pressure at the timing chain tensioner and prevent premature wear.
Comprehensive technical documentation and regulatory references
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AUDI Official Site
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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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