BMW X1 (2009 – 2015) Review
BMW X1 (2009 – 2015) At A Glance
The BMW X1 is the smallest model in the X line-up and - as BMW is proud to claim - was the first premium compact SUV on sale in the UK before the Audi Q3 and Range Rover Evoque. Don't be fooled by the pictures, the X1 is actually a lot more compact than it first appears plus it's priced pretty keenly too, making it an alternative to the likes of the Ford Kuga.
It is actually shorter than a BMW 3 Series Touring so parking isn't a problem, plus it drives well too with impressive handling and - unusually on a small BMW - a very forgiving ride. But where the X1 makes the most sense is in running costs.
It's available with xDrive four-wheel drive as you'd expect but there are also two-wheel drive version - badged sDrive - which unusually are rear-wheel drive rather than front. This means they still handle well in the BMW tradition, but fuel consumption and CO2 emissions are low. All X1s are powered by the same 2.0-litre diesel engine but in differing power outputs. The most frugal is the sDrive18d which is capable of averaging 54.3mpg while choosing the xDrive version still sees economy of 49.6mpg.
The top model is the twin-turbo xDrive23d with 204bhp but for most people the sDrive20d is the best blend of punchy performance and economy. On the road the X1 is comfortable and composed, tackling rough ground or long distance motorway cruises with equal aplomb, while passenger room for those in the back is impressively spacious.
BMW X1 (2009 – 2015) handling and engines
- Engines range from sDrive 16d to xDrive 20i Automatic
- Readers report Real MPG to be between 22–65 mpg
The X1 only comes as a diesel in the UK and despite the different badges, all use the same 2.0-litre engine, but in different power outputs. The most economical is the sDrive18d which has 143bhp on tap along with 320Nm of torque but still average 54.3mpg with low CO2 emissions of 136g/km, meaning annual car tax is very reasonable.
The reason this model is impressively efficient is that it's two-wheel drive - signified by the sDrive badge. Unusually it's actually rear-wheel drive, whereas all other two-wheel drive off-roaders like this are front-wheel drive, so it retains that excellent handling feel you expect of a BMW. All X1s come with an engine start/stop function too as part of the Efficient Dynamics fuel saving technology.
The four-wheel drive models are badged xDrive and the extra traction is very useful if you live in rural area where winter roads are rarely gritted and mud and ice can be a problem. Choosing a four-wheel drive mode doesn't mean getting stung by big increases in fuel consumption though - the xDrive18d is only slightly slower from 0-62mpg than the sDrive but you'd never notice in everyday driving, while economy is still 49.6mpg.
The most popular model is the sDrive20d with 177bhp which manages the 0-62mph sprint in 8.1 seconds and pulls very strongly in-gear for easy overtaking and motorway driving. It's still very economical with an average figure of 53.3mpg and works well with the standard six-speed manual gearbox, although this can feel a little springy and isn't particularly slick, especially if you try and change gear quickly.
The top of the range diesel is the xDrive23d which is fitted with twin turbos which helps boost maximum power to 204bhp along with 400Nm of torque. It originally came exclusively with a six-speed Sport automatic gearbox complete with paddle shifts on the back of the steering wheel. It's a decent gearbox and changes very smoothly but most people will probably prefer the six-speed manual version which was introduced in July 2010.
The 2.0-litre diesel engine that powers the X1 is quite noisy on start-up but is quiet enough on the move and barely noticeable at 70mph with the rev counter showing 2000rpm. Driving the X1 feels pretty much like getting behind the wheel of a 3 Series Touring. It's composed and reassuring while there's plenty of grip in tight corners. Body roll is slightly more evident than a 3 Series, which is inevitable given the higher centre of gravity, but perhaps the biggest surprise is the excellent ride quality - something unexpected in a small BMW.
Engine | MPG | 0-62 | CO2 |
---|---|---|---|
sDrive 16d | 58 mpg | 11.5 s | 128 g/km |
sDrive 18d | 54–58 mpg | 9.6 s | 128–136 g/km |
sDrive 18d Automatic | 57 mpg | 9.9 s | 132 g/km |
sDrive 20d | 53–58 mpg | 7.8–8.1 s | 129–139 g/km |
sDrive 20d Automatic | 48–57 mpg | 7.9–8.3 s | 132–155 g/km |
sDrive 20d EfficientDynamics | 63 mpg | 8.3 s | 119 g/km |
sDrive 20i | 40–41 mpg | 7.4 s | 162–165 g/km |
sDrive 20i Automatic | 42–42 mpg | 7.7 s | 157–160 g/km |
xDrive 18d | 50–51 mpg | 9.9–10.1 s | 144–150 g/km |
xDrive 18d Automatic | 52 mpg | 10.1 s | 143 g/km |
xDrive 20d | 49–51 mpg | 8.1–8.4 s | 145–153 g/km |
xDrive 20d Automatic | 46–52 mpg | 8.1–8.6 s | 143–164 g/km |
xDrive 20i | 37–38 mpg | 7.8 s | 176–179 g/km |
xDrive 20i Automatic | 39–40 mpg | 7.9 s | 167–170 g/km |
xDrive 23d | 47 mpg | 7.3 s | 158 g/km |
xDrive 23d Automatic | 45 mpg | 7.3 s | 167 g/km |
xDrive 25d | 48 mpg | 6.8 s | 154 g/km |
xDrive 25d Automatic | 51 mpg | 6.8 s | 145 g/km |
Real MPG average for the BMW X1 (2009 – 2015)
Real MPG was created following thousands of readers telling us that their cars could not match the official figures.
Real MPG gives real world data from drivers like you to show how much fuel a vehicle really uses.
Average performance
83%
Real MPG
22–65 mpg
MPGs submitted
502
BMW X1 (2009 – 2015) interior
- Boot space is 420–1350 litres
- Euro NCAP rating of five stars
Dimensions | |
---|---|
Length | 4454–4477 mm |
Width | 1798–2058 mm |
Height | 1545–1567 mm |
Wheelbase | 2760 mm |
It may be the smallest model in the X line-up, but it's not hard to see that the X1 is based on the BMW 3 Series Touring, with a very similar interior layout. What's surprising is that some of the plastics, most notably around the gear lever, don't feel very BMW-like and are quite hard. Thankfully, the rest of the cabin has the usual high-quality feel you'd expect from the German firm with soft-touch plastics and a well-built air to everything.
It's functional and easy to get to grips with, so although it's not as luxurious as the interior of the BMW X5, (there's a standard handbrake rather than an electric parking brake for example) it still works well and feels a cut above many alternatives at this price. The driving position is good - slightly raised compared to a normal saloon, giving a good view out - but not as elevated as a full-size 4x4. The X1 isn't as big or as high as it looks and sat alongside a BMW 3 Series you'll realise it's actually quite compact which makes it easy to park.
As you'd want from an offroader, the X1 is very practical. There's a standard hatchback opening and a 420-litre boot with a wide load floor. The rear seats fold fully down to open up the total area of 1350 litres which can carry a large amount of kit from bicycles to big bits of furniture. Those back seats are very comfortable too, with more leg and headroom than you'd expect to find in a car of this size.
Equipment from launch (October 2009):
SE is the only equipment level and comes with 17-inch alloy wheels with non-runflat tyres, rear parking sensors, two-zone air conditioning, electric windows, remote central locking, front foglights, a multi-function leather steering wheel, engine start/stop button, reach and rake adjustable steering, a CD stereo with an auxiliary input, Dynamic Stability Control (DSC) which includes traction control, ABS and cornering brake control plus rear Isofix child seat mounts. The xDrive18d and xDrive20d models get Hill Descent Control while the xDrive23d model comes with different alloy wheels, six-speed automatic gearbox, an automatically dimming rearview mirror, ambient lighting and chrome exterior trim.
BMW X1 (2009 – 2015) models and specs
Dimensions | |
---|---|
Length | 4454–4477 mm |
Width | 1798–2058 mm |
Height | 1545–1567 mm |
Wheelbase | 2760 mm |
Miscellaneous | |
---|---|
Kerb Weight | 1545–1670 kg |
Boot Space | 420–1350 L |
Warranty | 3 years / Unlimited miles |
Servicing | - |
Spare Wheel | |||
---|---|---|---|
Standard | Run-flat tyres |
Costs | |
---|---|
List Price | £24,230–£35,105 |
Insurance Groups | 18–28 |
Road Tax Bands | C–I |
Official MPG | 36.7–62.8 mpg |
Euro NCAP Safety Ratings | |
---|---|
Adult | - |
Child | - |
Pedestrian | - |
Overall | 5 |
On sale until August 2015
On sale until April 2014
SUV | |||
---|---|---|---|
Version | List Price | MPG | 0-62 |
sDrive 16d Sport 5dr | £25,230 | 57.6 mpg | 11.5 s |
sDrive 16d xLine 5dr | £26,230 | 57.6 mpg | 11.5 s |
sDrive 18d xLine 5dr | £27,330 | 57.6 mpg | 9.6 s |
sDrive 18d xLine Auto 5dr | £28,955 | 56.5 mpg | 9.9 s |
sDrive 20d xLine 5dr | £28,760 | 57.6 mpg | 7.8 s |
sDrive 20d xLine Auto 5dr | £30,485 | 56.5 mpg | 7.9 s |
sDrive 20i M Sport 5dr | £28,755 | 39.8 mpg | 7.4 s |
sDrive 20i M Sport Auto 5dr | £30,355 | 41.5 mpg | 7.7 s |
sDrive 20i SE 5dr | £25,755 | 40.9 mpg | 7.4 s |
sDrive 20i SE Auto 5dr | £27,355 | 42.2 mpg | 7.7 s |
sDrive 20i Sport 5dr | £26,755 | 40.9 mpg | 7.4 s |
sDrive 20i Sport Auto 5dr | £28,355 | 42.2 mpg | 7.7 s |
sDrive 20i xLine 5dr | £27,755 | 39.8 mpg | 7.4 s |
sDrive 20i xLine Auto 5dr | £29,355 | 41.5 mpg | 7.7 s |
On sale until May 2012
4 X 4 | |||
---|---|---|---|
Version | List Price | MPG | 0-62 |
sDrive 18d M Sport 5dr | £27,130 | 54.3 mpg | 9.6 s |
sDrive 18d SE 5dr | £24,780 | 54.3 mpg | 9.6 s |
sDrive 20d EfficientDynamics 5dr | £26,090 | 62.8 mpg | 8.3 s |
sDrive 20d M Sport 5dr | £28,560 | 53.3 mpg | 8.1 s |
sDrive 20d M Sport Auto 5dr | £29,990 | 47.9 mpg | 8.3 s |
sDrive 20d SE 5dr | £26,210 | 53.3 mpg | 8.1 s |
sDrive 20d SE Auto 5dr | £27,640 | 47.9 mpg | 8.3 s |
xDrive 18d M Sport 5dr | £28,245 | 49.6 mpg | 10.1 s |
xDrive 18d SE 5dr | £26,150 | 49.6 mpg | 10.1 s |
xDrive 20d M Sport 5dr | £29,710 | 48.7 mpg | 8.4 s |
xDrive 20d M Sport Auto 5dr | £31,140 | 45.6 mpg | 8.6 s |
xDrive 20d SE 5dr | £27,615 | 48.7 mpg | 8.4 s |
xDrive 20d SE Auto 5dr | £29,045 | 45.6 mpg | 8.6 s |
xDrive 23d M Sport 5dr | £31,855 | 47.1 mpg | 7.3 s |
xDrive 23d M Sport Auto 5dr | £33,395 | 44.8 mpg | 7.3 s |
xDrive 23d SE 5dr | £29,860 | 47.1 mpg | 7.3 s |
xDrive 23d SE Auto 5dr | £31,400 | 44.8 mpg | 7.3 s |
Model History
- July 2009: X1 unveiled
- July 2010: BMW X1 xDrive23d now available
- January 2011: X1 M Sport introduced
- July 2011: BMW X1 xDrive20d EfficientDynamics launched
- January 2012
- April 2012
- May 2012: Revised X1 announced
- May 2013
July 2009
X1 unveiled
BMW released details of its compact 'Sports Activity Vehicle' - the X1. It's slightly smaller than the X3 but still has five seats and 1350 litres of boot space. Power comes from a choice of three diesel engines and, for the first time on a BMW X product, the option to have rear-wheel drive (sDrive) or four-wheel drive (xDrive).
Standard wheel and tyre sizes are:
17-inch with 225/55/R17 tyres
18-inch with 225/50 R18 tyres
19-inch with 225/45 R19 tyres
Only diesel models are available in the UK - all using the same 2.0-litre diesel engine in various outputs. The sDrive18d and the xDrive18d feature four-cylinder powerplants with an all-aluminium crankcase and a single turbocharger with variable intake geometry. The 1,995cc engine produces 143bhp while peak torque is 320Nm from 1750rpm.
Offering a higher outright performance, the BMW sDrive20d SE and xDrive20d SE are powered by the same 1,995cc engine but offer 177bhp and 350Nm. The flagship model is the xDrive23d SE which comes only as a four-wheel drive. Still using a 2.0-litre engine, albeit with twin-turbocharger technology, the near flat torque curve with a peak output of 400Nm from 2000rpm promises effortless overtaking.
Most BMW X1s come as standard with a six-speed manual gearbox. However, buyers of the xDrive23d have a six-speed Sport automatic gearbox with gear change paddles. EfficientDynamics includes Auto Start-Stop which comes with all manual transmission to improve fuel consumption figures. The BMW X1 also has the full suite of EfficientDynmamics technologies including Brake Energy Regeneration, optimised aerodynamics and an optimum shift indicator.
All the main controls and dashboard displays are angled towards the driver while a range of storage compartments, trays and large door pockets provide a variety of places to keep personal effects. An owner that specifies one of the two available satellite navigation systems featuring the latest iDrive display, controller and Favourite Buttons gains a slightly revised interior layout to accommodate the system.
The interior of the BMW X1 can be further enhanced by opting for the new Design package. This sees Sport seats in Oyster Nevada leather, Anthracite headlining and Fineline Wave wood trim. The Oyster theme continuing to the lower part of the dashboard, all of the centre console and leather piping on the floor mats.
The BMW X1 went on sale in the UK on October 24 2009 while the sDrive18d and xDrive18d variants followed in December.
July 2010
BMW X1 xDrive23d now available
The range-topping BMW X1 xDrive23d is now available with a six-speed manual transmission, making it more efficient. The previously obligatory six-speed automatic transmission is now available as an option, while the manual version sees emission levels drop to 158g/km of CO2, from 167g/km for the automatic.
Peak power output remains 204bhp with a maximum torque of 400Nm while the zero to 62mph acceleration stays at 7.3 seconds. Average fuel consumption of a manual transmission equipped BMW X1xDrive23d is 47.1mpg.
January 2011
X1 M Sport introduced
The smallest member of the BMW X family, the X1, is the latest model to be enhanced with the addition of the popular M Sport specification. BMW's smallest Sports Activity Vehicle was an instant hit when it first went on sale in October 2009, going on to sell more than 6,300 units in 2010.
The M Sport specification sees 17-inch star-spoke M alloy wheels, chrome plated door sill finishers with M designation, High-gloss Shadowline exterior trim for the window surrounds, M Sport multi-function steering wheel, Sport seats and Anthracite headlining added. Prices start at £26,615 OTR for a BMW X1 18d sDrive M Sport and £27,710 OTR for 18d xDrive M Sport.
July 2011
BMW X1 xDrive20d EfficientDynamics launched
Powered by a 163bhp 2.0-litre four-cylinder diesel engine with a combined fuel consumption of 62.8mpg, emissions drop below a crucial threshold to hit 119g/km. This means that it attracts a company car taxation band of only 13 per cent for business drivers.
The latest X1 takes the relationship between sporty performance, athletic agility and fuel efficiency to a new level. TwinPower Turbo technology, which combines a variable geometry turbocharger and high-pressure fuel injection, gives maximum power at 4000rpm, while peak torque of 380Nm comes in at 1750rpm and remains constant until 2750rpm. A centrifugal pendulum absorber in the dual-mass flywheel damps out vibrations at low engine speeds, while new insulation technology eliminates engine noise inside the cabin.
The BMW X1 xDrive20d EfficientDynamics has Auto Start-Stop, Brake Energy Regeneration and an Optimum Shift Indicator adapted to suit the new engine’s characteristics. Electro-mechanical power steering, an air conditioning compressor, which can be disengaged, and tyres with reduced rolling resistance are fitted to Streamline-design light alloy wheels, all come as standard. The car also has a long final drive ratio to reduce engine revolutions at cruising speeds, but it still takes the car from zero to 62mph in just 8.3 seconds.
The most economical X product ever starts at £25,715 OTR when it goes on sale in September 2011.
The BMW Individual High Gloss Shadow Line roof rails are now an individual option, while the BMW ConnectedDrive package now includes the option of Real-Time Traffic Information. BMW’s ConnectedDrive system has been enhanced for 2011 for even more intelligent networking between the driver and the outside world.
Real Time Traffic Information (RTTI) is a superior system for warning drivers of hold-ups and calculating alternative routes to help avoid them. It is far quicker and more efficient than the Traffic Message Channel (TMC) currently used, transmitting data faster, and updating more frequently, via the SIM card integrated in the vehicle.
Courtesy of BMW Live, the driver’s mobile phone can serve as a modem to feed information to the car’s Control Display via Bluetooth. The system offers free RSS news feeds, weather information, Google Local Search, Google Panoramic and Street View. The RSS news feeds are read inside the car via BMW’s Text to Speech function. The facility will be available on the new BMW 1 Series in September, before being rolled out to other models.
The same camera system can also provide the driver more information through the new full-colour Head-up Display or the instrument panel. The Lane Departure Warning system can detect lane markings and sends a mild vibration through the steering wheel should the vehicle deviate from its lane without indicating. The Speed Limit Display reads both permanent and temporary speed limit signs and displays the current maximum permissible speed limit to the driver.
January 2012
First petrol-powered BMW X1 comes to the UK. From March 2013 the BMW X1 range expanded to include a new entry model and a petrol variant for the first time in the UK.
The new BMW X1 20i will be available in sDrive and xDrive, using the efficient BMW 2.0-litre TwinPower Turbo petrol engine with TwinScroll Turbo technology. This new engine emits just 162g/km CO2 (157g/km when fitted with the optional eight-speed automatic transmission) whilst still travelling from zero to 62mph in just 7.4 seconds, when mated to the standard six-speed manual transmission.
Further to the addition of the first petrol variants, there will be a new entry point to ownership in the X1 range with the launch of the BMW X1 sDrive16d. This new model emits just 128g/km CO2 and on the combined cycle delivering 57.6mpg, whilst still managing a zero to 62mph of 11.5 seconds.
Model |
Price from OTR |
Power |
Torque Nm |
Zero - 62mph Seconds 0 - 62 |
Top Speed Mph |
Combined |
CO2 Emissions g/km
|
BMW X1 20i sDrive |
£25,450 |
184 |
270 |
7.4 (7.7) |
127 |
40.9 (42.2) |
162 (157) |
BMW X1 20i xDrive |
£26,960 |
184 |
270 |
7.8 (7.9) |
127 |
37.7 (39.8) |
176 (167) |
BMW X1 16d sDrive |
£23,930 |
116 |
192 |
11.5 |
118 |
57.6 |
128 |
Available from March 2013, the BMW X1 is now available from just £23,930 OTR for a BMW X1 sDrive16d SE, while the BMW X1 sDrive20i SE is available from £25,450 OTR.
The number of BMW models meeting the EU6 regulations will increase from March 2013. With EU6 technology now optionally available on a wider range of cars including BMW Z4 sDrive18i, BMW Z4 sDrive20i and BMW Z4 sDrive28i, this brings the total number of EU6-compliant BMW models to 35.
April 2012
BMW X1 to be offered in the US market powered by BMW TwinPower Turbo petrol engines. This package of technology consists of twin-scroll turbocharging, High Precision Direct Petrol Injection, VALVETRONIC variable valve timing and Double-Vanos variable camshaft control. In both the award-winning six-cylinder in-line engine under the bonnet of the BMW X1 xDrive35i – developing 225 kW/306 hp – and the 180 kW/245 hp four-cylinder unit powering the BMW X1 sDrive28i and BMW X1 xDrive28i it ensures instantaneous power delivery, impressive pulling power and exceptional efficiency.
Both engines link up as standard with an 8-speed automatic gearbox and extensive BMW EfficientDynamics technology. Features including the Auto Start-Stop function (28i only), Brake Energy Regeneration, Electric Power Steering, the need-based operation of ancillary units and tyres with low rolling resistance all help to achieve a blend of performance and fuel economy unmatched by any rival.
The BMW X1 sDrive28i with customary BMW rear-wheel drive and the all-wheel-drive xDrive35i will be offered exclusively in the US market. The intelligent all-wheel drive of the BMW X1 xDrive35i and BMW X1 xDrive28i varies the distribution of drive between the front and rear wheels, as required. This electronically controlled power distribution ensures optimum traction and unbeatable directional stability in all weather and road conditions, as well as noticeably sportier responses through dynamically taken corners.
May 2012
Revised X1 announced
Now with wider range of diesel-only engines. With improved exterior styling, detail upgrades to the cabin and a new range of advanced diesel engines, the new X1 is perfectly placed to continue the sales success of the outgoing model. Every rear-wheel drive X1 now emits less than 130g/km of CO2, and with the option of a new eight-speed automatic gearbox combined with BMW’s award-winning EfficientDynamics technologies, the new BMW X1 range is more efficient than ever before.
Buyers can now also choose from two new models: Sport and xLine. In addition, SE and M Sport specifications receive an increase in standard equipment, further enhancing the value to the customer. Priced from £24,660 for the BMW X1 sDrive18d, the new BMW X1 goes on sale from July, 2012.
Model |
Power Hp |
Torque Nm |
0 – 62mph Seconds |
Top Speed mph |
Combined mpg |
CO2 emissions g/km |
Price from OTR |
BMW X1 xDrive25d |
218 |
450 |
6.8 |
142 (141) |
47.9 (51.4) |
154 (145) |
£31,860 |
BMW X1 xDrive20d |
184 |
380 |
8.1 |
133 (132) |
51.4 (52.3) |
145 (143) |
£27,580 |
BMW X1 sDrive20d |
184 |
380 |
7.8 (7.9) |
136 (135) |
57.6 (56.5) |
129 (132) |
£26,090 |
BMW X1 sDrive20d EfficientDynamics |
163 |
380 |
8.3 |
133 |
62.8 |
119 |
£26,090 |
BMW X1 xDrive18d |
143 |
320 |
9.9 (10.1) |
121 |
51.4 ( 52.3) |
144 (143) |
£26,150 |
BMW X1 sDrive18d |
143 |
320 |
9.6 (9.9) |
125 |
57.6 (56.5) |
128 (132) |
£24,660 |
May 2013
July 2013 sees the introduction of new Business models on the 1 Series, X1 and 3 Series EfficientDynamics ranges. The 99g/km 116d EfficientDynamics 5-door Hatch, the 119g/km X1 sDrive 20d EfficientDynamics, the 320i EfficientDynamics Saloon and both the 320d EfficientDynamics Saloon and Touring models, all come with enhanced equipment levels.
The BMW 1 Series Business model offers Dakota leather upholstery, BMW Business Media Package and heated seats. The X1 and 3 Series Business models build on this offering a 17-inch light-alloy wheel on the X1 and an exclusive 16-inch light-alloy wheel on the 3 Series.
Business models cost £1,400 on top of the standard EfficientDynamics models, yet offer a saving of more than £1,000 on the BMW 1 Series and BMW X1 and over £1,300 on the BMW 3 Series.
What to watch out for
If the car has Bluetooth and the owner has their bobile phone synced to the car then if the car is not locked / all electrics shut down the car will keep trying to search for the phone and drain the battery.
30-09-2013:Warning about the 'Mobile Application Preparation (6NR)' option at £130. This is ESSENTIAL because it enables the iPhone ‘BMW Connected Drive’ app, including web radio. BMW UK officially doesn’t or won’t support a retrofit of 6NR (though 'fixes' are available via idependent specialists).
28-05-2015:Report of cracking noise from plastic at either end of the dash when the car goes over a hump.
16-12-2016:Report of friction plate and starter ring gerar failure on 2012 BMW X1 2.0SE xDrive 8-speed automatic at 80,000 miles. Cost over £2000 to fix as the the torque converter and starter motor were damaged by metal bits flying around. First report of a problem with the 8-speed auto in any BMW.
04-02-2017:Turbo bearing oil seals of 2011/61 BMW X1 (N47) engine failed leading to engine running uncontrollably on its sump oil past 7,000rpm until it blew in a cloud of smoke.
14-03-2019:Report of failure of front diff of 2011 BMW X1 E84 2.0 diesel xDrive MSport at 48,000 miles. Feedback from the BMW specialist was the failure could have originated from oil in the diff gone bad or was bad in the first place. This was probably the root of the problem which caused input drive bearing to fail and the swarf inside caused the rest of the differential to fail also (or would do if continued driving). This oil is supposed to be sealed for life (and it would be BMW's definition of what life means, so does not get checked in routine servicing). £2,300 and replacement diff from BMW in Germany a week later, now X1 driving normally. (Specialist replaced a couple of X3 front diffs earlier this year also. Not their repair, but their Internet search found a failure with vehicle only done 20,000 miles. Mine was lucky at 48,000 but unlucky at it is over 6 years old.)