Buying guide: F13 6 Series
This glorious 6 Series is now more affordable to buy than ever before
One of the great appeals of the BMW range is that there really is something to suit all tastes within it. Of course, everybody’s needs are different, as are their budgets and priorities but, if you’re in the lucky position of having £20,000 or so to spend on a car that’s stylish, refined and yet remains a joy to drive, then you need look no further than the F13 6 Series.
Launched early in 2011, this third generation 6 Series saw BMW raise its game once again, returning the two-door coupé to its rightful position at the top of the desirability tree for those seeking a sleekly luxurious GT cruiser.
The much-criticised, Chris Bangle-inspired E63 model, with its drooped-nose, heavy-shouldered styling divided opinion. Few thought it a worthy successor to the timeless lines of the E24 6 that had gone before it, and it’s probably fair to assume that BMW lost traction among customers looking for the ultimate 2+2 autobahn stormer.
Somehow the designers managed to incorporate full-sized rear doors without spoiling the overall look of the car
So, it was important that the E63’s replacement got things back on track, and also had the sort of looks and cutting-edge technology that would appeal to a younger, more progressive audience. Well, the F13 certainly delivered. Gone were the slightly sad and awkward lines of the E63, to be replaced by the sort of sporting elegance that typifies motoring chic. The car was both beautifully proportioned and purposefully aggressive. It was low and sleek, with a long bonnet, steeply-raked windscreen, sweeping roofline and even included that BMW styling favourite, a Hofmeister kink.
As with the previous incarnation, this new 6 Series was available as both two-door coupé (F13) and Convertible (F12) but, a year after the initial launch, BMW pulled that proverbial rabbit out of the hat by introducing a four-door variant (F06) called, rather fittingly, the Gran Coupé. Somehow the designers managed to incorporate full-sized rear doors without spoiling the overall look of the car, and the new model added new levels of practicality and appeal to an already widely respected model.
Of course, being a 6 Series, the F12/F13/ F06 has always nestled up near the top of the BMW model range, in terms of both image and price. Go mad with the options list and it would have been possible to push the asking price of a range-topping 650i towards the £100,000 mark. Even the entry-level 640i, in SE trim, cost a thumping £61,000 back in 2012, so the levels of exclusivity befitting the car’s image and status were all but guaranteed.
It was important that the E63’s replacement got things back on track… and would appeal to a younger, more progressive audience
But fast-forward eight years to the present day, and the financial situation is very different. Like most expensive cars, vicious levels of depreciation cut 6 Series values savagely so that now, the savvy buyer with an eye for a beautiful bargain, can have their pick of the exclusive 6 Series range for the cost of a new Ford Focus 1.0-litre EcoBoost Titanium X, or a used, 2018 Hyundai i30 N Performance 2.0 T-GDi.
In practical terms, though, it’s not fair to compare a 6 Series with ‘ordinary’ saloons because anyone who buys one of these cars today will be entering into a very different ownership experience. For a start, you’ll be buying a prestige vehicle which, just because it’s depreciated to relatively affordable levels, isn’t going to be cheap to service and maintain properly. This third generation 6 Series is a complex model at which BMW threw just about every piece of electronic tech it had available at the time. So, while that engineering excellence certainly delivers a ride and drive that are superb in all respects, the flipside is that electronic gremlins and mechanical issues are likely to be more expensive to sort out than on a more run-of-the-mill vehicle.
So, to get a better idea about what problems may exist, and how much it’s likely to cost to put them right, I went to consult the uber-experienced Andy Walker who, as regular readers will know, runs independent BMW and MINI specialist, Walkers Autotech (tel: 01403 751646, walkersautotech.co.uk).
It’s not a model that attracts ‘boy racers’, so mechanically abused examples are rare
Evidently, he’s quite a fan of this model, both in terms of the quality of the car itself and for the reliability and durability levels it’s showing so far.
“Fundamentally this is a very good car,” he told me, “and it’s significantly better than the second generation E63 6 Series, in all respects. The design incorporates a lot of BMW’s F01 generation technology which makes a big difference in terms of driver feel and engine performance. While it’s still too early to be sure about how well the level of technology on this car will fare in the long term, the signs are promising. “We maintain a number of customers’ cars and, overall, they’re all proving to be very reliable so far,” he added. “This is helped by the fact that they are built around three tried and trusted power plants.” Model choice is quite a simple matter with this 6 Series; you choose the body style you want (Coupé, Convertible or Gran Coupé), then pair it with one of three engines. The 640i is powered by an N55 straight-six, twin-turbo three-litre, which is the engine that replaced the M54, and first appeared in the F07 5 Series Gran Turismo.
The 650i is powered by the N63 4.4-litre V8 twin-turbo engine – introduced in 2008 – that was the first to have the turbos nestled in the V between the cylinder heads. This motor was first used on the X6 E71, but also saw service in the 5 Series GT F07 and E70 X5.
A DIESEL OPTION?
Finally, and almost uniquely for a car of this type and stature, BMW offered the 6 Series with a diesel engine. This turned out to be something of a masterstroke, and the oil-burner comprehensively out-sold the petrol-powered alternatives thanks to its appealing mix of torque-heavy performance and economy.
The 640d utilises the N57 three-litre, straight-six, twin-scroll turbo diesel engine that was used successfully by BMWs all over the model range, including the E90 3 Series, F10 5 Series, the F01 7 Series, the F25 X3 and the E70 X5, to name but a few.
The march of time is very evident when comparing the interiors of this 6 Series with its predecessor. Everything’s significantly more modern, the instrument binnacle is very different and, of course, the whole infotainment side of things has come on in leaps and bounds. The audio-visual interfaces are much improved, there’s superior Bluetooth connectivity and everything is just that much more convenient and pleasant to use.
Despite now being eight years old, Andy says that the enhanced tech levels inside this generation of 6 Series aren’t throwing up any significant signs of trouble. This is just as well because, with the car set at the price point it was when new, the original buyers tended to be in a position to be fairly generous with their optional extras choices. Consequently, many of the models now available as used buys are very well specced.
The one caveat in all this, though, is that the engineering and electronics used in this generation of 6 Series were cuttingedge at the time. “There’s no getting away from the fact that these cars can be expensive to repair if things go wrong,” warned Andy. “A high-spec F13 6 Series could utilise as many as 30 electronic control modules to run all the systems on the car. The cost of replacing these will vary from £200 to £2,000 a time, plus the additional cost of programming new units to the vehicle, once fitted.
“The way that this generation of car was designed, means that any programming or software updating that may be required is a complex procedure, that has to be done using the BMW online platform. Accordingly, such work can only be tackled by a BMW dealership or a well-equipped and knowledgeable specialist.
“While it is possible to get into the onboard systems using third-party diagnostic software, doing so can be a risky business that’s prone to throwing up additional problems. We’ve come across a number of cars that have been fitted with aftermarket components, or ‘moneysaving’ secondhand control units, which have actually caused a bigger problem than the one being solved.”
BMW IN CONTROL
“BMW has worked hard with all the F generation models, to limit who is able to work successfully on them and, as a result, it’s now very difficult to do anything other than buy a new control unit from them and use BMW software to programme it to the car.
“Third party software will get you partway through the control unit programming process but, typically, not be able to complete it. This will usually leave a degree of functionality unavailable, because the binary codes needed to activate them are only available online, from BMW. On the plus side, software updates on this generation of car can now be performed much more quickly, and are issued from Germany more frequently.”
Quite where this will leave owners further down the line, however, is a matter for debate. It’s arguable that a 15-year-old 650i that’s fallen out of the dealership network and which, by that stage, has a relatively low value, could well be difficult and expensive to get repaired. Fortunately, as Andy points out, electronic reliability is certainly much better on the systems fitted to these cars than it used to be, say, 10 years ago.
But Andy warns that the fitment of nonstandard or aftermarket components can be sufficiently disruptive, in electronics terms, to scupper an official software update. Such modifications can also have a knock-on effect on any subsequent repairs which involve reprogramming, as the system won’t allow it because the car is no longer ‘standard’.
TIMING CHAIN ISSUES
So, starting with the 640d, I asked Andy to summarise the mechanical issues that buyers should be aware of. “One of the main problems encountered with this engine is a stretched timing chain,” he explained. “This happens in exactly the same way as it does on the X5 and 5 Series models, but the trouble is that it’s impossible to assess the state of the chain without physically looking at it.
“The best you can do is to insist on a cold start when you’re viewing the car, and listen for the characteristic rattling sound as this happens. The same noise can also sometimes be noticed when the engine is very hot, and it comes from the back of the engine – the timing chain is situated between it and the gearbox.”
The chain can actually break if the problem’s ignored; Andy hasn’t seen this happen on a 640d yet, but it’s certainly starting to happen with similarly-aged 5 Series models. He believes that the problem stems essentially from the chain not being strong enough for the job. “While I can’t really complain as it keeps us busy,” he told me with a wry smile, “it does make me despair from an engineering point of view. Thinking back 20 or 30 years, we never had to change timing chains, but now we’re having to do it all the time, across the whole model range.
“Usage does play a part (lots of idling seems to increase the problem), and longlife servicing is a factor as well, I’m sure.
More frequent engine oil changes (every 15,000 miles) will certainly help prolong chain life but, having said that, we do see some pretty random failures as well, which suggests that the chain simply isn’t strong enough for the application.”
Changing the timing chain is a difficult and expensive job. Due to its location at the back of the engine, it’s a good 13-14 hours’ work, according to Andy, which equates a £2,000+ bill, wherever you get it done. Of course, if you leave it and the chain breaks, then you’re probably looking at £4,000-£5,000 to put things right. So, buyers and owners certainly need to be aware of the risks associated with timing chain problems, and should be listening hard for that tell-tale rattle.
Other than this, though, there are few characteristic problems to worry about. Andy hasn’t come across any turbo failures on this model, but does feel that they’re probably still a bit young for that to be occurring. However, the F10 5 Series has been around for longer, and this engine isn’t suffering in this way, which bodes well. The diesel injectors seem to be more reliable than they have been in the past, which is another bonus.
If there are any doubts over the engine’s smoothness of running when it’s warm (at idle or under load), then that could be a problem. However, this engine – in common with most others from this era – is so highly monitored, that the slightest of faults will illuminate a warning light on the dash anyway so, if there’s nothing showing, then you can typically assume that all’s well.
So far, Andy says that all the ancillary components have proved pretty much trouble-free, which is good. Bear in mind, though, that even quite common components on this car will be expensive to replace. A replacement alternator, for example, will costs about £700 from BMW (it’s a ‘smart’ unit) and a new radiator will be costly to replace, too. There isn’t a huge amount of aftermarket support yet for this model so, in most cases, the only option is to stick with BMW.
There’s good news concerning the entry-level 640i which, Andy says, is proving extremely reliable. “I’ve not seen any significant issues with the N55 straight-six yet; the 640i seems to be a very durable model, across the board. So as far as I’m concerned, it’s looking like a good option in terms of reliability.
Unfortunately, the situation isn’t quite so rosy for the top-of-the-range 650i V8 model; it’s simply not as reliable. For example, older versions are already suffering with valve stem oil seal wear. The most effective way to test for this is to get the engine good and warm during a test drive, allow it to idle for five minutes and then boot the throttle. If this is greeted by a cloud of blue smoke from the exhaust, then oil’s getting past the stem seals and rectification work will be required.
Andy explained, “The onset of this issue is perhaps accelerated by infrequent engine oil changes, but it’s the fact that the rubber seals harden with age that’s at the root of the problem. These engines use such thin oil nowadays, and run at such high temperatures that the environment is very unforgiving.
“An increase in oil consumption is also a good indicator of valve stem seal wear (or a problem with the turbochargers), and putting it right is a big job that requires the removal of the engine, gearbox and subframe, and is likely to cost about £2,500.”
“The timing chain can be similarly problematic on this V8 as it is on the N57 diesel engine, so it makes sense to change this and the stem seals at the same time. In addition, problems with the fuel injectors – denoted by a dashboard warning light or poor running – are another issue to watch out for with this engine. BMW’s standard policy is to replace all eight at the first sign of trouble, but my approach is usually to replace them two at a time.
“Trouble can often be caused by straightforward carbonisation, in which case a cleaning agent can be used in situ to put things right. Alternatively, an injector may have developed a mechanical problem, and the only way that can really be confirmed is with a smooth-running test on a cold engine. Quite careful diagnostics is needed to identify this type of issue, as it’s not always severe enough to trigger a warning light, but will certainly produce running issues. Also, it can be that adjacent injectors might be compensating for the faulty one, which can confuse the picture. Replacement injectors cost £200 each.” Having said all of this, the V8 certainly isn’t an engine that Andy would shy away from as an ownership proposition. The issues we’ve mentioned here are by no means a certainty, so it’s important not to reject this motor purely for fear that things might go wrong.
GEARS AND SPRINGS
As far as gearboxes are concerned, the seven- and eight-speed units used on this 6 Series are brilliant. Andy says that they’re fast-changing, smooth and reliable. However, a transmission fluid change is something that new owners really ought to consider, even though these gearboxes are ‘sealed for life’ units. Andy is a great believer in not leaving this important lubricant untouched, and advocates changing it after 80,000-100,000 miles. It is quite an expensive job, though.
The correct fluid costs £36 a litre so, with a seven-litre capacity, you’re looking at £252 in oil alone. Then, when you add the cost of a new filter and sump pan assembly, plus labour (it’s not a quick job), you’ll be lucky to get away with a bill that’s less than £600. But this, of course, is cheaper than a transmission rebuild.
Very occasionally you may come across a gearbox that’s leaking fluid, so always make sure that you have a good look underneath for any signs of oil seepage (both from the gearbox and the engine. It’s not unknown for the differential to leak also, usually from the output seals and, although this may not sound like much of a problem, dealing with it is relatively involved.
Putting this right requires a special tool to undo the propshaft at the front, so that the diff can be dropped. Also, you can’t seperate the driveshafts, you have to remove the hubs to pull them out of the diff erential which, as you can imagine, makes the whole job quite costly.
UNDER THE SURFACE
In terms of running gear, the suspension set-up used on this model is generally very reliable, and Andy hasn’t come across any major issues yet, even on high-mileage examples. However, it’s still worth listening for suspicious, bumpinduced clonking on the test drive, which could be worn lower arms. These will cost about £300 each from BMW, leading to a £1,000 bill for replacing both at the front. It also makes sense to check for any advisories noted during the car’s most recent MoT test.
The car isn’t unusually heavy, so brake wear shouldn’t be any worse than on a corresponding model, although the bigger, heavier-engined versions are likely to put more loading on both brakes and suspension components at the front. Discs from BMW are expensive, but there are some decent aftermarket alternatives now available at more reasonable prices. The dreaded wheel-cracking can be an issue to watch for, too. These cars use runflats which are expensive to replace and can make wheel damage more likely. So, it always pays to check the condition of both the wheels and the tyres, and to beware if there’s a tyre pressure warning light illuminated on the dash.
Inside things should be pretty good. There’s no doubting how well the 6 Series is screwed together, or the fact that all models will offer comfortable and durable accommodation. However, there’s lots of electronic equipment to be carefully checked, so make sure that everything works. It’s all too easy to overlook a malfunctioning seat adjustment motor or inefficient air con, in the general excitement of a test drive.
This generation of 6 Series has plenty going for it, and is a car that can now represent fantastic value as a used buy. Prices are dipping ever more attractively, and the fact that the car was so expensive when new means that most are very well equipped as far as optional extras are concerned.
The choice between two-door Coupé, Convertible and four-door Gran Coupé models really is a matter of personal preference. The Coupé is the purest design but only offers two doors and cramped rear seats. The Convertible has an electrically-operated fabric roof which can be a security worry, while the Gran Coupé delivers four-door practicality and proper rear seats without ruining the overall shape of the car.
This isn’t the sort of car that gets passed from pillar to post, so it’s rare that you’ll come across one that’s had six or seven owners. Also, it’s not a model that attracts ‘boy racers’, so mechanically abused examples are rare.
This is a sophisticated GT car that was designed to provide the discerning owner with an appealing mix of sportscar-like performance and limousine-like levels of refinement. On the flipside, of course, running costs are likely to be a little more pricey than most but, having said that, reliability levels so far are pretty encouraging.
Nevertheless, even the basics such as brakes, tyres and batteries will be expensive to replace; there’s no getting away from that. You can’t expect to run a complex and beautifully-engineered car without having to spend a bit of cash now and then. But, if you keep on top of regular maintenance and make the effort to change the engine oil more frequently than BMW recommends, then there’s no reason why one of these fine cars shouldn’t reward you with years of enjoyable and luxurious service.
Left to right: Few would argue that this model of 6 Series, two-door coupé – the F13 – is one of the most attractively-styled models in the entire BMW range. Apart from great proportions, it has individuality, which is becoming an increasingly rare commodity.
Neatly-styled from every angle, the F12/13/06 6 Series was built on a slightly shortened version of the F10 5 Series platform.
The interior is plush and comfortable, as befits a range-topping coupé.
The 2,993cc straight-six diesel engine produces 313hp and powers the most popular 640d. So far, it’s proved to be encouragingly reliable.
The F12 Convertible version was introduced in 2011 and featured an electrically-operated, fabric hood.
The F06 Gran Coupé 6 Series was launched in 2012, and was 11cm longer and 2cm taller than the Coupé, to accommodate the full-sized rear seats and doors. Rear accommodation in the Coupé is tight, although the seats are beautifully sculpted and trimmed.
If you need a genuine, four-seater capacity, then you’ll have to go for the Gran Coupé version.
WHAT TO PAY?
Nowadays, a range-topping BMW 650i M Sport F13 that, in 2012, would have cost its original owner £73,500 (excluding any options), could now be yours for just £18,000. But if you don’t fancy supporting the petrol-guzzling habit of the 4.4-litre V8, then similarly-aged 640ds can be found for around £13,000! If you’re more interested in some wind-in-the-hair motoring, then an early Convertible model, with 60,000 or so on the clock, could be yours for around £15,000. There doesn’t seem to be much differentiation – in terms of price – between diesel- or petrol-powered Convertibles although, as with the Coupé and Gran Coupé models, the number of diesels available greatly outnumbers those with petrol engines. At the top of the price scale, £30,000 will buy you a low-mileage, 2016 640d Convertible, while similar Coupés are about £1,000 cheaper, whether petrol- or diesel-powered. Interestingly, the top prices for the Gran Coupé are very similar to those of the Convertible.
Petrol-powered cars are certainly in the minority on the used market today. This is the 4.4-litre V8 that powers the 650i, and there are issues to watch for when buying. Whichever body style you choose, this generation of 6 Series is an accomplished driver’s car.
TECHNICAL DATA FILE
MODEL 640i M Sport / 650i M Sport / 640d M Sport / 640d Gran Coupé M
CAPACITY (cc/cyl) 2,979/6 / 4,395/V8 / 2,993/6 / 2,993/6
MAX POWER (bhp) 321 / 449 / 313 / 313
MAX TORQUE (lb ft) 332 / 479 / 465 / 465
0-62MPH 5.3 / 4.6 / 5.3 / 5.4
TOP SPEED 155 / 155 / 155 / 155
ECONOMY (mpg) 36.7 / 31.7 / 51.4 / 49.6
KERB WEIGHT (kg) 1,760 / 1,870 / 1,815 / 1,885