NEW CARS - CITROËN 2.5 TD/2.0 16V

Fuel for thought

Saturday morning, before daybreak. The XM's fuel gauge indicates that it has about three-quarters of a tank of petrol on board.

Saturday evening, just before midnight. The gauge has dipped to around the one-quarter mark, maybe just a little below.

In-between times, the car has travelled from south-east London to Cheshire, and covered a fair few urban miles before commencing its return journey. It is some way south of Birmingham when you finally stop to refuel.

Such are the potential time-saving benefits of a diesel. With care, it should be possible to cover 600-plus miles between stops, thanks to the 17.6 gallon tank. The XM 2.5 turbodiesel is a particularly good example of the breed, and spearheads the oil-burning segment of the revised XM range. It is one of two new engines introduced during the summer, and it boasts more torque than any other diesel passenger car in the UK 217 lb ft at just 2000 rpm.

Its performance is superb. Beneficial economy aside, it provides silent, high-speed cruising and punchy mid-range acceleration. It's not sparklingly fast (although quoted top speed is a respectable 124 mph), just astonishingly smooth. Only when you fire it up from cold does it offer any aural clues that it might have a passing relationship to an FX4 cab. . .

The XM is an extremely practical long-distance tourer, bereft of all sporting pretensions. In addition to a restyled (for the better) interior, remote deadlocking and alarm, coded immobiliser, steering-wheel mounted stereo controls and a driver's airbag, the XM has also been endowed with revised suspension. The new front geometry is said to reduce pitch, dive and roll, but the fact remains that the XM turns into a squidgy mess if you try to thread it through a series of corners at speed.

For all that, the £23,950 2.5 TD comes thoroughly recommended. If you want cossetting, look no further. The aforementioned London-Cheshire return trip, undertaken with absurd haste, induced absolutely zero driver fatigue.

The other new powerplant is the petrol-fed, 2.0, I6v four-cylinder, which powers the entry-level XM SX (at £15,995). This proved more disappointing.

Although its performance capabilities are ultimately similar to those of the turbodiesel, it requires a far greater deal of effort to extract them. Our test car, fitted with the four-speed automatic, felt gutless, and a touch harsh. It's still has peerless ride quality, of course, and, in fairness, it's a reasonable slab of car for the money. But once you've driven the 2.5 TD, most other XMs are going to seem a little second-rate. . .It's as comfortable an A-B conveyance as there is, and it'll get most of the way to Z before you need to refuel. S A