The Jaguar AJ28 is a 4,196 cc, V8 petrol engine produced between 1998 and 2009. It belongs to Jaguar's AJ — V8 family, featuring double overhead camshafts (DOHC), 32 — valve configuration, and sequential multi — point fuel injection. In standard calibration, it produces 220 kW (299 PS) and 400 Nm of torque, delivering smooth power delivery with strong mid — range responsiveness for grand touring applications.
Fitted primarily to the XJ (X308/X350) and XK (X100) models, the…
Jaguar
Production years 1998–2002 meet Euro 3 standards; 2003–2009 models comply with Euro 4 .
The Jaguar AJ28 is a 4,196 cc V8 petrol engine developed for luxury sedan and grand tourer platforms (1998–2009). It features DOHC architecture with four valves per cylinder and sequential fuel injection to ensure smooth power delivery. Designed initially for Euro 3 and later upgraded to Euro 4 emissions standards, it balances refinement with adequate performance for its era.
| Parameter | Value | Source |
|---|---|---|
Displacement | 4,196 cc | |
Fuel type | Petrol | |
Configuration | V8, DOHC, 32-valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 89.0 mm × 84.0 mm | |
Power output | 220 kW (299 PS) @ 6,150 rpm | |
Torque | 400 Nm @ 4,100 rpm | |
Fuel system | Sequential multi-point fuel injection (Siemens MS43) | |
Emissions standard | Euro 3 (pre-2003); Euro 4 (2003–2009) | |
Compression ratio | 10.7:1 | |
Cooling system | Water-cooled | |
Turbocharger | Not applicable | |
Timing system | Chain-driven (dual-row primary, single-row secondary) | |
Oil type | Refer to vehicle handbook / manufacturer specification | |
Dry weight | 205 kg |
The Jaguar AJ28 was used across Jaguar's X308/X350 platforms with longitudinal mounting and shared architecture with Daimler for select applications. This engine received platform-specific tuning-shortened intake runners in the XK and revised exhaust manifolds in the XJ-and from 2003 the facelifted XJ Series III adopted updated ECU mapping and swirl flap design, creating interchange limits. All adaptations are documented in OEM technical bulletins.
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Field reports and technical service bulletins highlight component wear patterns under high-load operation. Adherence to manufacturer service intervals and approved fluid specifications is critical for long-term reliability.
Analysis derived from manufacturer technical service bulletins and industry workshop records. Repair procedures should follow manufacturer guidelines.
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The AJ28 engine is fundamentally robust with good longevity when properly maintained. Pre-2003 models are more prone to swirl flap issues, while later revisions show improved reliability. Regular oil changes with correct specification (10W-40 WSS-M2C159-C) and use of premium fuel are essential. Well-maintained units can reliably exceed 180,000 km.
The most documented issues are inlet manifold swirl flap failure (especially pre-2003), intake valve carbon buildup due to port injection, and oil leaks from ageing valve cover gaskets. Timing chain tensioner wear can occur with poor maintenance. These are addressed in Jaguar service bulletins and technical documentation.
The AJ28 4.2L V8 petrol engine was used in the Jaguar XJ (X308, 1998–2003), XJ (X350, 2003–2009), and XK (X100, 1998–2006). It was also fitted in the Daimler Super Eight (2000–2005). All models comply with Euro 3 or Euro 4 standards depending on production year.
Aftermarket ECU tuning is common on the AJ28 platform, but increasing boost or altering engine parameters accelerates component wear, impacts emissions compliance, and may void vehicle warranties. Any modifications should be evaluated carefully by a qualified specialist.
In combined driving, the AJ28 achieves approximately 14.5–16.5 L/100km (17–20 mpg UK). Highway consumption is around 12.0 L/100km (24 mpg UK), while city driving may reach 18.0 L/100km (16 mpg UK). Real-world economy depends on driving style and vehicle weight, with the XK being slightly more efficient than the XJ.
Yes, the Jaguar AJ28 is an interference engine. If the timing chain fails or jumps, piston-to-valve contact will occur, resulting in severe internal engine damage. Maintaining the chain system through proper oil and timely servicing is critical to prevent costly repairs.
Jaguar specifies SAE 10W-40 synthetic oil meeting WSS-M2C159-C standard. This oil is essential for maintaining hydraulic lifters, chain tensioners, and valve train longevity. Change intervals should not exceed 12,000 km or one year, whichever comes first, to ensure optimal engine protection.
Comprehensive technical documentation and regulatory references
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Regulatory Stability
EU regulations are referenced using CELEX identifiers for long-term stability.
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.
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