From 2001 to 2009, the company produced the Jaguar AJ25 2.5-liter gasoline engine, which was fitted to the British company’s most well-known models, including the S-Type and X-Type. In essence, this motor belonged to the Duratec V6 family of power units.

AJ-V6 series: AJ20, AJ25, AJ30.
Specifications
| Production years | 2001-2009 |
| Displacement, cc | 2495 |
| Fuel system | distributed injection |
| Power output, hp | 195 – 200 |
| Torque output, Nm | 240 – 250 |
| Cylinder block | aluminum V6 |
| Block head | aluminum 24v |
| Cylinder bore, mm | 81.65 |
| Piston stroke, mm | 79.50 |
| Compression ratio | 10.5 |
| Features | DOHC |
| Hydraulic lifters | no |
| Timing drive | chain |
| Phase regulator | on the intake shaft |
| Turbocharging | no |
| Recommended engine oil | 5W-30 |
| Engine oil capacity, liter | 5.9 |
| Fuel type | petrol |
| Euro standards | EURO 3 |
| Fuel consumption, L/100 km (for Jaguar X-Type 2009) — city — highway — combined |
15.0 7.6 10.3 |
| Engine lifespan, km | ~350 000 |
| Weight, kg | 170 |
The engine was installed on:
- Jaguar S-Type 1 (X200) in 2002 – 2007;
- Jaguar X-Type 1 (X400) in 2001 – 2009.
Disadvantages of the Jaguar AJ25 engine
Despite having numerous expensive and uncommon parts, the device is fairly dependable;
The primary issues are related to drying gasket-related air leaks;
Additionally, the electrically driven geometry change system frequently malfunctions in the intake; the crankcase ventilation valve needs to be cleaned on a regular basis to prevent lubricant from pressing through all the cracks; and high mileage causes oil consumption because of stuck piston rings.
