Jaguar Ingenium diesel (AJ200D)

Jaguar Land Rover's own modular four-cylinder family, in diesel and petrol forms, built to replace the Ford- and PSA-derived engines the company had used previously — fitted across the XE, XF, F-Pace, Evoque, Discovery Sport and Defender.

The diesel's known problem is the timing chain, and specifically the chain and tensioner on earlier examples, where wear produced a rattle and, in a proportion of cases, a jumped chain. It was common enough to generate extended-warranty attention. As always the noise precedes the codes, and on this engine a start-up rattle is not something to monitor.

The emissions stack — EGR, particulate filter and AdBlue — supplies the rest, with the familiar short-journey duty cycle behind most of it and oil dilution as the consequence worth catching early. The petrol Ingenium is a different proposition with the ordinary direct-injection turbo profile: intake-valve carbon and oil-dependent turbocharger life.

AJ is Jaguar's prefix for every engine it has ever built and carries no family information at all — the AJ-V6, AJ-V8 and AJ16 share it and share nothing else. Within Ingenium the designation does the work: AJ200D is this 2.0 diesel, AJ20D6 the 3.0 diesel six, and the petrol engines of the same family are a separate page.