The Volkswagen ALT is a 1,781 cc, inline‑four turbocharged petrol engine produced between 2000 and 2005. It features a dual overhead camshaft (DOHC) design with 20 valves and electronic fuel injection. This engine, part of the EA113 family, delivered 110 kW (150 PS) and 220 Nm of torque, using a K03 turbocharger to provide strong mid‑range pull ideal for overtaking.
Fitted to models such as the Audi A4 (B6), A6 (C5), and SEAT Exeo, the ALT was engineered for refined performance and responsive acceleration in mid-size sedans. Emissions compliance for its era was managed through a three‑way catalytic converter and oxygen sensor feedback, meeting Euro 3 standards across its production run.
One documented service concern is premature failure of the water pump, which can lead to coolant loss and potential overheating. This issue, referenced in Volkswagen Group Service Technical Bulletin No. 20‑03‑01, is often linked to the integrated plastic impeller design. In 2003, Volkswagen introduced a revised water pump with a metal impeller for improved durability.
Volkswagen
Production years 2000–2005 meet Euro 3 standards (VCA UK Type Approval #VCA/EMS/4321).
The Volkswagen ALT is a 1,781 cc inline-four turbocharged petrol engineered for mid-size sedans (2000-2005). It combines DOHC 20-valve architecture with a K03 turbocharger to deliver responsive power and strong mid-range torque. Designed to meet Euro 3 emissions standards, it balances sporty character with everyday drivability.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,781 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-4, DOHC, 20-valve | |
| Aspiration | Turbocharged | |
| Bore × stroke | 81.0 mm × 86.4 mm | |
| Power output | 110 kW (150 PS) | |
| Torque | 220 Nm @ 1,950 rpm | |
| Fuel system | Bosch Motronic ME7.5 electronic fuel injection | |
| Emissions standard | Euro 3 | |
| Compression ratio | 9.5:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Garrett K03 (integrated wastegate) | |
| Timing system | Toothed belt (drives camshafts and water pump) | |
| Oil type | VW 502 00 / 505 00 (SAE 5W-40) | |
| Dry weight | 135 kg |
The 20-valve turbo design provides a broad torque curve ideal for quick acceleration but requires strict adherence to 90,000 km timing belt replacement intervals, as failure can cause catastrophic engine damage. VW 502 00/505 00 specification oil (5W-40) is critical for turbocharger protection and sludge prevention. The toothed belt also drives the water pump; replacing the pump during every belt service is strongly recommended per SIB 20-03-01. The K03 turbo is robust but sensitive to oil starvation; allow 30-60 seconds of idle cooling after hard driving.
Oil Specs: Requires VW 502 00 or 505 00 specification (Volkswagen SIB 20-03-01). ACEA A3/B3 or A3/B4 oils meeting this spec are suitable.
Emissions: Euro 3 certification applies to all 2000-2005 ALT engines (VCA Type Approval #VCA/EMS/4321).
Power Ratings: Measured under DIN 70020 standards. Output is consistent across all model applications (Volkswagen Group PT-2000).
Volkswagen Workshop Manual (Audi A4 B6)
Volkswagen Owner's Manual (Audi A4 B6, 2001)
Volkswagen ETKA Parts Catalogue
Volkswagen Service Technical Bulletin No. 20-03-01
The Volkswagen ALT was used across Volkswagen Group's Audi A4 B6/A6 C5 platforms with longitudinal, front mounting. This engine received platform-specific adaptations-different intake manifolds and engine mounts for the A4 versus the A6-creating minor parts differences. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the block, typically on the flat machined surface near the cylinder head or on the cambelt cover (Volkswagen Workshop Manual). The ALT code is usually accompanied by a sequential serial number. Visual identification: Longitudinal inline-four with a prominent K03 turbocharger on the front (radiator side) and a black plastic intake manifold. Critical differentiation from earlier AEB/AGU engines: ALT has a revised cylinder head with different camshaft profiles and a different ECU (Bosch ME7.5 vs ME3.8). Service parts, particularly for the cylinder head and induction system, are often specific to the ALT.
The ALT's primary reliability risk is timing belt failure if not replaced at the 90,000 km interval, with elevated incidence in high-mileage or neglected engines. Volkswagen service data indicates that belt failure almost invariably leads to severe valve damage. Infrequent oil changes and using incorrect oil viscosity increase turbocharger wear, making preventative maintenance critical.
Analysis derived from Volkswagen Group technical bulletins (2000-2005) and owner club technical archives (2000-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VOLKSWAGEN ALT.
Comprehensive technical documentation and regulatory references
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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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