Four engines are available in a Jaguar XE, and the 2.0-litre, four-cylinder turbo-diesel in two of the less costly models, the XE 2.0d Prestige and R-Sport, is easily the least thirsty of them. It consumes just 4.2 litres/100km on the official test (city and country combined).
This engine accelerates the car effortlessly. In many driving conditions it feels more responsive than all but the most powerful XE engine, the supercharged V6 petrol of the XE S – and it matches that.
One reason you might not choose this smooth diesel is that you expect to take your XE out of the city only occasionally. The diesel uses a particulate filter to keep exhaust soot out of the atmosphere, and the filter needs regular highway drives to keep it from becoming clogged.
Another might be that you prefer the way a petrol engine drives. The petrol-engined XEs all feel sportier, and when you ask for all the go you can get, they are quicker.
The least thirsty of the petrol engines are the 2.0-litre, four-cylinder, turbo petrols that drive the XE 20t and 25t (available in Prestige, R-Sport and Portfolio trim). Both use 7.5 litres/100km on the official test - even though the retuned 25t delivers about 20 per cent more power than the 20t.
In a real-world comparison conducted for the April 2016 edition of Wheels magazine, an XE 25t averaged 9.8 litres/100km, using a half-litre more than the most frugal of five medium sedans reviewed, a BMW 330i.
The thirstier petrol engine is the 3.0-litre supercharged V6 fitted to the XE S. It is about 70 percent more powerful than the engine in the 20t, and uses 8.1 litres/100km on the official test.
All engines have an automatic stop-start system, which saves fuel in urban driving. It shuts down the engine when you stop, and starts it again when you take your foot off the brake pedal to drive away.
Petrol engines in the XE have shorter service intervals than the diesel, at 12 months or 16,000km. The diesel needs a service every 24 months, or 34,000km.
Every Jaguar XE has an eight-speed conventional automatic gearbox.