Diesel is fast becoming the default fuel for buyers of large family 4x4s in this country, particularly for those who aren't blessed with a bank account of the bottomless variety. The superior fuel economy along with the lower CO2 emissions and the improving refinement of modern oil-burning engines all play their part but where does all this leave petrol? It's true that petrol engines deliver better performance but do we really want performance in a big family-orientated offroader? Volvo obviously think some of us do and their plush XC90 4x4 is better equipped than most to handle it. That's why they offer the latest model with a sweet 3.2-litre straight-six petrol engine.

Volvo's XC90 occupies a curious position in the large 4x4 arena. Its pricing, equipment levels and interior quality match it squarely up against luxury 4x4 models like BMW's X5 and the Mercedes M-Class but the Volvo also offers seven seats mounted in a versatile interior that's more MPV than 4x4. Its off road ability is best described a patchy but on the tarmac it displays a high degree of composure and refinement that's on a par with many executive saloons. It's a hard one to nail down and no mistake but this unorthodox collection of abilities has won the XC90 a large and loyal following in the UK.

The 3.2-litre petrol engine sits slap bang in the middle of the XC90 engine range, above the big selling D5 diesel and below the 4.4-litre V8 that was introduced to give the car added impetus at the very top end of the luxury 4x4 segment. The majority of buyers will discount the V8 straight off the bat, or at least as soon as they get their heads around the 20mpg combined fuel economy. The 3.2-litre is more economical but not by much, posting an average in the region of 24mpg compared to the 34mpg you should expect from the diesel. Emissions may be another sticking point, with the 3.2 engine producing 281g/km of CO2 and the D5 pumping out 219g/km. Also counting against the V8 is the hefty premium of nearly £8,000 that it commands over the 3.2-litre but with the 3.2 requiring only an extra £1,000 in addition to the oil-burner's asking price, buyers are presented with an interesting conundrum.

"The 3.2-litre engine is smooth in its power delivery and pleasantly hushed when cruising"

With 235bhp on tap, this straight-six engine is not lacking in power, which it deploys through Volvo's 'Geartronic' automatic transmission (there's no manual option). It will get the XC90 to 60mph in 8.9s before running out of puff at 130mph. The 182bhp D5 diesel requires 10.3s to hit the 60mph barrier and eventually achieves a 121mph top speed so the additional £1,000 outlay gets you a whole lot of extra capability.

Unlike many large 4x4 vehicles, the XC90 is well equipped to take full advantage of its engines' power output. It can't quite match the BMW X5 which is widely regarded as the class benchmark for on-road handling but it isn't too far off. The car is not averse to being hurried down a fast B-road, although twistier sections unsettle it a tad, but its key strengths are ride and refinement. The 3.2-litre engine is smooth in its power delivery and pleasantly hushed when cruising, while the XC90's suspension does a great job of ironing-out the road surface to keep passengers comfortable.

With the XC90's entry-level S trim reserved for the cost-effective D5 diesel engine, the 3.2-litre straight-six powerplant enters the equation at the SE trim level priced from £36,435. Here there's leather faced seats with electric adjustment for the driver's seat and a 6 CD autochanger in addition to the generous standard specification. 18" alloys also feature to boost the exterior appearance. Above the SE sits the SE Sport with its sharper responses and more dynamic appearance. Next comes the SE Lux with its full leather upholstery, heated front seats, Bi-Xenon headlamps and various cosmetic titbits, then you have the Executive which really is crammed with high-tech features.

The XC90's cabin really is excellent, the most versatile of any large 4x4. The rearmost row of seats is really only suitable for kids but leg and headroom elsewhere is plentiful. That rear row can be folded down so that it completely disappears under the floor leaving an extensive load area, while the three seats in the middle row slide back and forth individually to create extra legroom. These middle seats fold flat in an operation that's refreshingly simple and that results in a truly monstrous carrying capacity for those weekend trips to the municipal dump.

Safety is another prime Volvo strength. Parent company Ford were, after the Explorer/ Firestone debacle, glad to hear that the XC90's innovative Roll Stability Control (RSC) system received the World Traffic Safety Symposium Manufacturers Award. Volvo has approached this thorny issue with a three-pronged attack. In order to prevent the XC90 going dirty side up in the first instance, sophisticated gyroscopically-controlled stability software steadies even the most radical lane changing behaviour. Should you hit a kerb or ditch and roll the car, it features a boron-reinforced roof to prevent the upper body deforming. Finally, the XC90 also features curtain airbags that stay inflated ten times longer than normal bags in order to ensure passengers are kept away from flying glass and insulated from doorframes during a roll.

The Volvo XC90 is a luxury 4x4 designed around the family and that makes it something of a unique proposition in today's large 4x4 sector. Volvo obviously got the balance right, however, because the car has been a storming success for them since its launch. One suspects that cash-strapped family buyers will gravitate towards the lower running costs of the diesel engine while those intent on money-no-object luxury will opt for the V8 and the opulent Executive trim. This leaves the 3.2 straight six option as a bridge between the two extremes. It's more expensive to run than the oil-burner but for just £1,000 more, it's usefully quicker and very refined. That will be enough to persuade some buyers, especially those who don't cover particularly high mileages and so won't find the pinch at the pumps quite as fierce.

TOP 3 XC90 DEALS

The results below show the top XC90 deals on buyacar

	Volvo XC90 3.2 SE 5dr Geartronic Off Road
	ETR	Mthly £643	Saving £4,456	Price £31,860
	Volvo XC90 3.2 SE Lux 5dr Geartronic Off Road
	ETR	Mthly £682	Saving £4,716	Price £33,655
	Volvo XC90 3.2 Executive 5dr Geartronic Off Road
	ETR	Mthly £849	Saving £5,105	Price £41,096

typical 11.25% APR

PCP finance quote over 48 months,  10,000 miles pa,  deposit of £1000