BMW X6 Review (2015-2018)

Based on the chassis and mechanical package of the third-generation BMW X5, the X6 has a sloping rear roofline that robs it of some of the practicality of a regular SUV. That's why BMW wants us all to regard the X6 as a Sports Activity Coupe, or SAC, to temper expectations over ultimate luggage space. Still, there’s sufficient room in the boot for most people’s baggage requirements and the 40:20:40 split folding rear seat arrangement adds to the X6’s flexibility, even if the seats don’t fold fully flat. While the original car was criticised for a lack of headroom in the rear, the X6 is fine for all but the tallest passengers, and the rear bench is now shaped to accommodate three across; previously the X6 only had seats for two.

In most examples the X6 boasts very supportive sports seats up front, although the optional Comfort seats are worth tracking down if the rest of the car’s spec meets your requirements. You sit SUV-high and vision to the front and sides is excellent. To the rear it’s less so because of the thick rear pillars, which may explain why the X6 has front and rear parking sensors as standard.

The engine line-up is relatively simple. There are two turbocharged 3.0-litre straight-six diesel engines, one with one turbo producing 254bhp the other with two turbos good for 309bhp, which power the X6 xDrive30d and xDrive40d, respectively. There’s a third diesel - with triple turbochargers and 376bhp - under the bonnet of the M50d. Petrol engine fans can choose between the twin-turbo 444bhp 4.4-litre V8 powering the xDrive50i, or go all-out with the X6 M which uses the same engine but tuned to give 568bhp. All these engines can rustle up stonking performance, especially in the mid-range, and for the most part are smooth and refined. And all are teamed with an eight-speed torque converter-type automatic gearbox.

For a car with such impressive get-up-and-go, and which handles, grips and steers so deftly, the X6 rides surprisingly well. Most versions feature adaptive dampers with Comfort and Sport settings as standard, while the M50d and X6 M boast full adaptive suspension that includes anti-body roll technology and air suspension at the rear.

The BMW X6 is an immensely sophisticated, high performance luxury car crammed with extraordinary technology, and yet it doesn’t cost as much to run as you might think. Correction: it doesn’t cost as much to service as you might think, even at an official BMW dealer. Some more recent examples of the X6 may still be within the three-year warranty period, and there’s kudos in having a full set of official service stamps on your car’s service history. Older X6s can be more cheaply serviced in the large UK network of respected independent BMW specialists.

Service intervals on the X6 are dictated by the car’s on-board servicing computer, which takes into account your mileage and the manner in which you drive. The maximum gap between visits to the workshop is two years or 18,000 miles, and services alternate between minor and major. At the time of writing, BMW’s servicing price menu quoted £217/£545 for the xDrive30d and 40d, £219/£569 for the M50d, £261/£661 for the petrol xDrive50i, and £223/£810 for the X6 M. The first service price quoted in each instance is essentially an oil and filter change, the cost of which drops to £129 across the board once your X6 is four years old.

Big car. Heavy car. Four-wheel drive car. Fast car. The odds stack up against you at the fuel pumps. Most economical of the X6s, by a small margin, is the xDrive30d, which in old money is claimed to give 47mpg but under the stricter WLTP testing regulations is down to around 33mpg. That’s still commendable for a hulking great car weighing 2.3 tonnes, but chances are you’ll be getting a few mpg less than that if you start using the car’s performance. Go a bit crazy in the xDrive50i and X6 M and consumption will fall into the teens.

Rates of annual road tax range from £205 through to £565 and the X6 sits in insurance groups 41-50, depending on the model. As for tyres… On the X6 M the tyres are made specially for it, and the rears are £375 each while the fronts are £305. Even on the xDrive30d M Sport the fronts cost between £118 and £172, while the bigger rears are from £140 to £210 each.

The original X6 and the second-generation X5 on which it was based had a range of reliability issues affecting the engines, gearbox, and suspension. BMW has maybe learnt its lessons from those problems because to date the second-generation X6 seems not to have suffered any major traumas despite the oldest versions of it being five years old. Doubtless some owners will have had rogue cars that have tested their patience, but no significant pattern of repeated problems has yet emerged.

What we have seen mention of, however, are numerous random electrical glitches and failing sensors, few of which appear to have required expensive fixes, but sometimes took the car off the road for days at a time. In the US, where by law car makers have to declare such things, BMW has issued many Technical Service Bulletins (TSBs, which represent advice for dealer workshops on how to fix recurring minor, and sometimes major, problems) for the X5 and X6. These relate to several areas of the cars, from creaking steering columns, troubles with the electrical adjustment of the steering column and front seats, creaking sounds from the front axle, noisy aircon, malfunctioning cameras for the Surround View system, and countless other minor irritants.

Because there are so many electrical systems on the X6 it would be very hard for you to try every piece of equipment to ensure that it works. Which is why before you buy an X6, it's a good idea to book it in for an in-depth diagnostics session at a BMW dealer to find out what might have gone wrong with the car in the past and what might be wrong with it right now.

On the mechanical side of things there are reports of failing high-pressure diesel fuel pumps, high oil consumption on a handful of petrol V8s, and on older cars, leaks from the air suspension system at the rear (where fitted).