The Jaguar AJ-V6 engine is a specialized version of Ford's Duratec 25/30 V6. One notable addition is the use of variable valve timing, a feature also shared with Mazda's version of the engine. It is available in 2.0 L, 2.5 L and 3.0 L displacements.

Jaguar's AJ-V6 engine has an aluminium engine block and aluminium DOHC cylinder heads. It uses SFI fuel injection, has 4 valves per cylinder with VVT and features fracture-split forged powder metal connecting rods and a one-piece cast camshaft, another differentiator from the Ford and Mazda versions.

Jaguar press shot of the AJ-V6

AJ20

The AJ20 2.1 L (2099 cc) version has an 81.6 mm bore and 66.8 mm stroke. Although it displaces nearly 2.1 litres, it is marketed as a "2.0". It produces 157 hp (117 kW) and 148 ft-lb (196 Nm). The compression ratio is 10.75:1.

This engine is used in the following vehicles:

Jaguar X-Type 2.0 (UK)

AJ25

The AJ25 is a 2.5 L (2495 cc) version built in Ford's Cleveland, OH #2 factory. It is stroked to 79.5 mm. It delivers 192 hp (143 kW) at 6800 RPM with 178 ft-lb (241 Nm) of torque at 3000 RPM from 10.3:1 compression.

This engine is used in the following vehicles:

Jaguar S-Type 2.5 (UK)
Jaguar X-Type 2.5

AJ30

The AJ30 is a 3.0 L (2967 cc) version and is the most common, especially considering the Duratec 30. It has an 89 mm bore and shares the 2.5's 79.5 mm stroke. In the X-Type, it produces 231 hp (172 kW) and 209 ft-lb (284 Nm).

This engine is used in the following vehicles:

2000-2004 Jaguar S-Type 3.0
2002-2004 Jaguar X-Type 3.0
Jaguar XJ6
2006 "baby" Land Rover