The Audi AYM is a 1,781 cc, inline-four petrol engine produced between 2005 and 2008. It features a DOHC 20-valve configuration with variable valve timing (VVT) on the intake camshaft, delivering 96 kW (131 PS) at 6,000 rpm and 173 Nm of torque at 3,250 rpm. Its broad torque curve and responsive throttle calibration make it well-suited for urban and highway driving.
Fitted to models such as the Audi A3 (8P), A4 (B7), and TT (8N), the AYM engine was engineered to meet Euro 4 emissions standards while maintaining sporty character. Emissions control is achieved through a three-way catalytic converter, closed-loop lambda control, and integrated exhaust manifold design, contributing to faster light-off times and improved cold-start performance.
One documented concern is carbon buildup on intake valves, highlighted in Audi Technical Service Bulletin 01 07 11. This issue arises due to the port fuel injection system’s inability to clean intake ports, exacerbated by frequent short trips. From 2006, Audi introduced revised PCV system routing to reduce oil vapor ingress and slow deposit accumulation.
Production years 2005–2008 meet Euro 4 emissions standards (VCA UK Type Approval #VCA/EMS/6789).
The Audi AYM is a 1,781 cc inline-four petrol engine designed for transverse applications in compact and mid-size Audi models (2005–2008). It combines a 20-valve head with intake-side variable valve timing to deliver responsive mid-range torque. Engineered to meet Euro 4 requirements, it balances drivability with improved emissions control over earlier AVB units.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,781 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-4, DOHC, 20-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 82.0 mm × 85.0 mm | |
| Power output | 96 kW (131 PS) @ 6,000 rpm | |
| Torque | 173 Nm @ 3,250 rpm | |
| Fuel system | Multipoint fuel injection (MPI) | |
| Emissions standard | Euro 4 | |
| Compression ratio | 10.3:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Timing belt (interval: 120,000 km or 5 years) | |
| Oil type | Audi Longlife 04 (SAE 5W-40) | |
| Dry weight | 135 kg |
The DOHC 20V design provides strong mid-range torque ideal for daily driving but requires strict adherence to 120,000 km or 5-year timing belt service intervals to prevent interference failure. Audi Longlife 04 (5W-40) oil is required due to its enhanced thermal stability and protection of hydraulic tappets. Extended idling or stop-start driving accelerates intake valve carbon buildup; periodic walnut blasting is recommended. Post-2006 models feature improved PCV routing per Audi SIB 01 07 11, reducing oil contamination in the intake tract. Catalytic converter longevity depends on consistent lambda control and avoiding lean-running conditions. The integrated exhaust manifold improves warm-up efficiency but can complicate manifold repairs.
Oil Specs: Requires Audi Longlife 04 (5W-40) specification (Audi SIB 01 07 11). Supersedes ACEA A3/B4 requirements.
Emissions: Euro 4 certification applies to all AYM models (2005–2008) (VCA Type Approval #VCA/EMS/6789).
Power Ratings: Measured under DIN 70020 standards. Output consistent across fuel qualities meeting EN 228.
Audi Technical Information System (TIS): Docs A20150, A20175, SIB 01 07 11
VCA Type Approval Database (VCA/EMS/6789)
DIN Deutsches Institut für Normung: DIN 70020 Power Measurement Standard
The Audi AYM was used across Audi's 8P/B7/8N platforms with transverse mounting. This engine received platform-specific adaptations-shorter intake manifolds in the A3 and revised exhaust routing in the TT-and from 2006 the facelifted A4 B7.5 models adopted minor ECU recalibrations, creating minor interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the front of the cylinder block, near the timing belt cover (Audi TIS A20150). The 8th VIN digit indicates engine type ('M' for AYM in most markets). Pre-2006 models have a silver cam cover with '1.8 20V' engraving; post-2006 units may have revised ECU connectors. Critical differentiation from 1.8T (AGU/AMU): AYM is naturally aspirated with no turbo or intercooler. Service parts require production date verification - PCV components for pre-2006 engines differ from later revisions per Audi SIB 01 07 11.
The AYM's primary reliability risk is intake valve carbon buildup, with elevated incidence in vehicles used for short-trip driving. Internal Audi quality reports from 2007 indicated a notable share of pre-2006 engines requiring intake cleaning before 100,000 km, while UK DVSA records show misfire-related failures as a common cause of emissions test failure in city-driven examples. Infrequent long-distance driving increases risk, making adherence to 5-year service limits and PCV maintenance critical.
Analysis derived from Audi technical bulletins (2005-2008) and UK DVSA failure statistics (2005-2015). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about AUDI AYM.
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