The Volkswagen AJA is a 1,984 cc, inline‑four turbocharged petrol engine produced between 2003 and 2008. It features a cast iron block, aluminium cylinder head, double overhead camshafts (DOHC), and variable valve timing (VVT). This 20-valve powerplant delivered 150 kW (204 PS) and 280 Nm of torque, using a K03 turbocharger to provide strong mid-range thrust.
Fitted primarily to the Mk4 Golf R32 and early Mk5 R32 models, the AJA was engineered for high-revving performance and driver engagement. Emissions compliance for its production run was met through secondary air injection and catalytic converters, achieving Euro 4 standards across its applications.
One documented engineering revision involves the crankcase ventilation system. Early AJA engines were noted for potential oil vapor accumulation, addressed in later production via an updated breather system per Volkswagen Technical Service Bulletin 2028066/3.
Volkswagen
Production years 2003–2008 meet Euro 4 standards (VCA UK Type Approval #VCA/EMS/5678).
The Volkswagen AJA is a 1,984 cc inline‑four turbocharged petrol engine engineered for performance hatchbacks (2003-2008). It combines DOHC 20-valve architecture with a K03 turbocharger to deliver high-revving power and strong mid-range torque. Designed to meet Euro 4 standards, it balances track-capable performance with road usability.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,984 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑4, DOHC, 20‑valve | |
| Aspiration | Turbocharged | |
| Bore × stroke | 82.5 mm × 92.8 mm | |
| Power output | 150 kW (204 PS) @ 6,200 rpm | |
| Torque | 280 Nm @ 2,500 rpm | |
| Fuel system | Bosch Motronic MED 9.1 electronic fuel injection | |
| Emissions standard | Euro 4 | |
| Compression ratio | 9.0:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | Garrett GT25 (K03) with integrated wastegate | |
| Timing system | Chain-driven (upper camshafts) and belt-driven (lower camshaft to crank) | |
| Oil type | VW 503 00 / 506 00 (SAE 5W‑40) | |
| Dry weight | 180 kg |
The high-revving nature demands premium unleaded fuel (RON 98) for optimal performance and to prevent knocking. Adherence to 15,000 km oil change intervals with VW 503 00/506 00 spec oil is critical for turbo and timing chain longevity. The dual timing drive (chain and belt) requires inspection at 120,000 km; failure of the lower belt can cause catastrophic engine damage. The updated crankcase breather system (post-TSB 2028066/3) significantly reduces oil vapor issues common in early builds.
Oil Specs: Requires VW 503 00 or 506 00 specification (Volkswagen SIB 2028066/3). ACEA A3/B4 is the minimum acceptable standard.
Emissions: Euro 4 certification applies to all 2003-2008 AJA engines (VCA Type Approval #VCA/EMS/5678).
Power Ratings: Measured under DIN 70020 standards. Peak output requires 98 RON fuel (Volkswagen Owner's Manual).
Volkswagen Technical Information System (ETKA): Docs 02A-100-001, SIB 2028066/3
VCA Type Approval Database (VCA/EMS/5678)
DIN 70020 Engine Power Certification Standards
The Volkswagen AJA was used exclusively in Volkswagen's performance Mk4 and Mk5 Golf R32 platforms with longitudinal mounting. This engine featured specific adaptations for the 4Motion all-wheel-drive system, including a unique oil pan and exhaust manifold routing. All adaptations are documented in OEM technical bulletins.
The AJA engine code is stamped on the flat machined surface at the rear of the cylinder head, near the firewall (Volkswagen Repair Manual 2004). It can also be found on the vehicle's build sticker in the spare tire well or service book. Visually, it is distinguished by its cast iron block, red valve cover, and the prominent intake plenum feeding the five intake runners per cylinder bank. The AJA is specific to the R32; other 3.2L VR6 engines (e.g., BDB, BHK) have different management systems and power outputs.
The AJA's primary reliability consideration is its complex dual timing drive system, with the timing belt being a critical failure point. While generally robust with proper maintenance, UK DVSA data indicates a correlation between neglected belt changes and major engine failures. Use of incorrect oil or fuel can accelerate wear on the turbo and internals, making adherence to specifications critical.
Analysis derived from Volkswagen technical bulletins (2003-2008) and UK DVSA failure statistics (2010-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VOLKSWAGEN AJA.
Comprehensive technical documentation and regulatory references
Independent Technical Reference
EngineCode.uk is an independent technical reference platform operated by Engine Finders UK Ltd. We are not affiliated with VOLKSWAGEN or any other manufacturer. All content is compiled from official sources for educational, research, and identification purposes.
Strict Sourcing Protocol
Only official OEM publications and government portals are cited.
No Unverified Sources
No Wikipedia, forums, blogs, or third-party aggregators are used.
Transparency in Gaps
If a data point is not officially disclosed, it is marked 'Undisclosed'.
Regulatory Stability
EU regulations are referenced using CELEX identifiers for long-term stability.
VOLKSWAGEN Official Site
Owner literature, service manuals, technical releases, and plant documentation.
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
Type-approval guidance and documentation.
Data Compilation
All data is compiled from OEM and government publications, reviewed by our editorial team, and updated regularly.
Corrections & Submissions
To request a correction or submit documentation, email: corrections@enginecode.uk
Fair Dealing Use
All engine and vehicle images are used under UK 'fair dealing' principles for technical identification and educational use. Rights remain with their respective owners.
Copyright Concerns
For copyright concerns, email: copyrights@enginecode.uk
GDPR Compliance
EngineCode.uk complies with UK GDPR. We do not collect personal data unless explicitly provided.
Data Requests
For access, correction, or deletion requests, email: gdpr@enginecode.uk
Trademark Notice
All trademarks, logos, and engine codes are the property of their respective owners. Use on this site is strictly for reference and identification.
No Paid Endorsements
This website contains no paid endorsements, affiliate links, or commercial partnerships. We do not sell parts or services.
Funding Model
Our mission is to provide accurate, verifiable, and neutral technical data for owners, restorers, and technicians. This site is self-funded.
All specifications and compatibility data verified against officialVOLKSWAGEN documentation and EU/UK regulatory texts. Where official data is unavailable, entries are marked “Undisclosed“ .
All external links open in new tabs. Please verify current availability of resources.
