Audi SQ7 TDI | PH Used Buying Guide
Huge and hugely out of fashion – but also one of the very best fast SUVs made in recent years
By Tony Middlehurst / Sunday, 17 September 2023 / Loading comments
Key considerations
- Available for £32,000
- 4.0-litre V8 diesel triple turbo, all-wheel drive
- 664lb ft should be enough for most purposes
- Tramps on somewhat and sounds good while doing so
- Surprisingly economical and so far pretty reliable
- Sadly, they only made four years’ worth
Torque. If that’s the stuff you like and you have no hangups about filling up from the black pump, you should be interested in the subject of today’s buying guide. The Audi SQ7 4.0 TDI was released in 2016, not long before diesel became a dirty word, as an alternative to contemporary premium diesel offerings from BMW, Porsche and Range Rover. It was the first Audi S model in the Q7 lineup and the most powerful diesel SUV you could get at the time.
The MLB Evo-platformed SQ7 was a weighty thing at a couple of bags of sugar under 2.4 tonnes, but you wouldn’t be noticing any sluggishness on the road thanks to the 664lb ft of poke – the same as the LaFerrari – that was available from not much above tickover. For that, you could thank the clever linking up of the two sequential turbochargers to an EPC (Electric Powered Compressor) running off a 48-volt electrical sub-system that was powered by a lithium-ion battery below the luggage compartment. This lag-reducing wheeze won Audi at least one major innovation award. With that, plus 429hp, quattro all-wheel drive and a slick 8-speed ZF gearbox the SQ7 was fully armed to whoosh through the 0-62mph run in just 4.8 seconds.
If you think these numbers are mad for a seven-seat SUV, the monstrous Q7 6.0 V12 TDI that Audi put out in 2008 was even madder. This beast, the only production V12 diesel ever produced, pumped out a paint-stripping 738lb ft plus 493hp from its R10 racecar-derived lump, but the six-speed box and near-2.7 tonne weight kept the 0-62mph time up in the mid fives and the combined fuel consumption figure down to 25mpg.
Reflecting the more efficiency-oriented philosophy of the age, the 4.0 V8 SQ7 was relatively abstemious with an official combined fuel consumption figure of 38.2mpg. Mid-30s was a very achievable average and more than 40mpg was available on a tour, a remarkable figure really given the size of the thing. The SQ7’s fuel tank was 3 Imperial gallons smaller than the V12’s, but it still held nearly 19 Imperial gallons so you could technically at least rumble on for over 700 miles between fills.
The SQ7 was also a less outlandish purchasing proposition than the V12 too, which at nearly £100k back in 2008 was nearly twice as expensive as any other Q7 model on sale at the time. Compared to that the TDI was a relative bargain at under £71k in 2016.
A year after that, a Vorsprung edition was released at £88,295, which was a meaty £15,400 more than the regular model at that time. For that, you got 22-inch Audi Sport wheels, blacked-out grille, roof rails and side window trims, running boards, Matrix LED headlights, scrolling indicators, heated seats, Alcantara headlining, diamond-stitched Valcona leather with extra moo on the door handles and armrests, and a bunch more fun stuff.
Mild hybrid (MHEV) tech was announced in mid-2019 for fitment as standard across the Q7 lineup. The diesel engine was discontinued in 2020, its place under the bonnet being taken by the twin-turbo petrol 4.0 V8 already used by cars like the Bentley Continental GT and various Audi RS models. This unit dished up 500hp and 568lb ft from 2,000-4,100rpm, making the 2.25-tonne SQ7 TFSI good for an impressive 4.5-second 0-62mph time, but the price for that was a combined consumption figure of 23.3mpg, as near as dammit 15mpg worse than the TDI that we’re looking at today.
There’s no doubt that the SQ7 TDI was a huge car with a huge appetite for cargo and distance but it wasn’t as cumbersome to drive as it looked, especially if it was fitted with the all-wheel steering option that was part of the optional Driving Dynamics Sport Pack. We’ll look more at that a little later, but for now let’s just say that it took the daunt out of a daunting British multi-storey car park and made the SQ7 a much better handling device than it had any right to be.
Despite being a diesel the SQ7 was also a range-topper so it had Audi’s legendary quattro all-wheel drive system, full seven-seat capability and all the accoutrements you’d expect from a luxury vehicle.
If this is all starting to sound pretty attractive to you, the only question remaining may be ‘what will it cost me to get into an SQ7 TDI?’. The answer might surprise and/or delight. Damaged/repaired cars can be as little as £26k, but even for for an intact car with fewer than 100,000 miles on the clock the realistic bottom dollar is a very reasonable sounding £32k. At this end of the SQ7 TDI market mileage doesn’t seem to matter too much. You could still be paying the same sort of money for a car with nearer to 150k on it. This suggests a degree of market respect for the TDI’s longevity, but is that borne out in the real world? Let’s take a look.
SPECIFICATION | AUDI SQ7 TDI (2016-20)
Engine: 3,956cc V8 32v turbodiesel
Transmission: 8-speed automatic, all-wheel drive
Power (hp): 429@3,750-4,750rpm
Torque (lb ft): 664@1,250-3,250rpm
0-62mph (secs): 4.8
Top speed (mph): 155
Weight (kg): 2,395
MPG (official combined): 38.2
CO2 (g/km): 194
Wheels (in): 21
Tyres: 285/45
On sale: 2016-20
Price new: £70,970
Price now: from £32,000
Note for reference: car weight and power data is hard to pin down with absolute certainty. For consistency, we use the same source for all our guides. We hope the data we use is right more often than it’s wrong. Our advice is to treat it as relative rather than definitive.
ENGINE & GEARBOX
The SQ7’s V8 BiTDi engine was the first Audi diesel to feature the company’s Valvelift tech, which used variable exhaust valve opening to control the operation of the sequential turbos, the second one beginning to light up from 2,000rpm and becoming noticeably active from 2,500rpm. At really low revs, before any of the conventional exhaust-gas turbocharging effort came into play, the EPC was chipping in with electronic turbine-assisted induction.
In all honesty, there was still a delay in the initial delivery of power but once you’d got past that the performance was mountainous. When you were cranking hard out of a bend the thrust was necessarily tempered by the traction electronics and by the excellent but understandably questioning ZF torque converter gearbox. You could forgive it for that. It must have been tough for the trans ECU to choose the right cog when just about any of them was capable of being effortlessly prodded into action by the mighty motor. In waft mode, there were few cars to beat it. Luxuriating in the torque was just a matter of flexing your toe. It sounded good too, the relaxed throb of eight cylinders being subtly supplemented by a sound actuator whose output was controllable through the drive select system. Sport mode in automatic was the best one to be in for truly effortless progress.
Everything was big about the SQ7, right down to the 7-litre (over 1.5 gallons!) windscreen washer bottle. Fortunately, the list of common engine and transmission problems hasn’t been so big, but there are a few things to watch out for.
Turbos can die, and not just the conventional ones either. The EPC electric compressors didn’t last forever. Poor step-off and failure of the stop-start system are your main clues to its demise. Confirmation would come with a P15B700 fault code. You could probably continue without buying a new one (no PH responsibility on that one, ahem) and that is something you might want to try because as of Sept ‘23 new EPCs were retailing at £2,277 including VAT.
Each of the conventional turbos had its own dedicated air filter and MAF sensor. Because they operated sequentially, with the second one only coming in at the sort of revs you could easily miss out on altogether, there was a natural tendency for the filter on the first turbo to get dirtier than the second one.
There were two EGR systems on the SQ7 along with two DPFs. The N80 purge valve was designed to redirect random fuel vapours back into the intake manifold. Rough idling and increased fuel consumption was your clue that this was conking out.
Excess oil warnings could sometimes be down to the dilution of the oil with diesel fuel, as a result of either incomplete DPF regen cycles or the oil never getting up to temp on short journeys in colder climates. Separately, oil could leak from the valve covers, sump or oil filter housing.
Faulty knock sensors are not unknown. These would trigger a check engine light, poor fuel consumption and reduced power. Coils and plugs were under extreme pressure in the SQ7 and could fail. Some owners of later models from the last two years of production have reported gearshifting delays or even slipping out of gear. Independents specialising in German cars will typically charge £230-£240 for an annual or 6-monthly to be on the safe side oil and filter service.
CHASSIS
SQ7 suspension was multi-link at both ends with adaptive air as standard. For many of those who had sampled many different Audis over the years (eg motoring journalists) the balance of stability, control and comfort offered by the SQ7’s chassis established a kind of long-awaited ideal for a marque that had previously struggled to impress in that department. You’d never call it engaging – a diesel Cayenne S felt noticeably lighter on its feet – but the Audi was able to hang on for grim death in corners without slumping into monster understeer. The steering itself was good by any standards, let alone Audi’s quite poor ones. You couldn’t help but admire its all-round composure. In Comfort mode, it was a struggle to find anything to criticise. Even the optional 22-inch wheels brought no really bad ride downsides.
The optional Driving Dynamics Sport Pack included a torque-vectoring ‘sport’ rear diff, all-wheel steering and the electromechanical roll defeat system previously showcased in the Bentley Bentayga. It wasn’t cheap at £5,700 but it worked brilliantly in the SQ7. With that lot in place, the SQ7 handled incredibly well taking into consideration its Gulliverian dimensions. The active anti-roll tech, which decoupled on straight roads to optimise ride quality, negated just about all of the pig-on-stilts queasiness through high-speed corners that you would expect from such a towering machine.
Later (2019-20) cars could suffer from air suspension failure, usually related to the compressor. From a generic used car perspective, very few air suspension systems don’t experience some sort of leak or compressor problem at some point in their lives. That’s one of many reasons why pwnership of, and an ability to use, a diagnostic unit is pretty much essential when shopping for cars of this complexity. Something like an Ancel VD500 is available off eBay for under £40.
The quattro all-wheel drive plus the 60mm body hoist that you got with the ‘Off Road’ setting gave the SQ7 surprising ability on slippery ground, but throw some deepish snow at it and you soon found out it was no Discovery. It was a road-biased SUV. Carbon ceramic brakes were optionally available in some markets, but not in the UK for some reason. Parts for the standard steel brakes are not cheap. Cracked CV boots would allow grit to contaminate the joints, with predictable results. Suspension bushes take a battering on any heavy car and the SQ7 was certainly in that club.
BODYWORK
The SQ7’s brutalist looks didn’t come in for a lot of praise in 2016 but they seem perfectly acceptable now. The panoramic roof was massive and visibility generally was excellent.
Aluminium has become the de rigueur material for big performance cars and the SQ7 stuck to that template. Q7s had a bit of a reputation for accumulating quite a bit of water inside as a result of drain grommets becoming blocked over time. As far as we know the same system pertains to the SQ7 (and many other VAG products) and, again as far as we know, is still used today. It’s something to be aware of.
Driver’s door modules can fail, killing all the controls for that door and the passenger one on the same side. Q7 ball and socket windscreen wiper linkages had a habit of becoming detached. Audi wanted a fortune (£400 approx) for the complete linkage but some owners found that a judiciously applied rubber band would do the trick. For a longer-term fix windscreen wiper repair clips are available for under a tenner online.
Matrix LED headlights could be prone to condensation. There is a silicone DIY fix, but getting the units out to do the job is not a walk in the park.
INTERIOR
Any 2016 mainstream car with a £70k asking price had to earn that tag inside as well as out. The SQ7 pulled that one off with total conviction. The cabin didn’t have the organic warmth of a top-spec Range Rover but it was superbly functional either as a seven-seater with an acceptable boot or as a five-seater with a huge (1,890 litres) one, where it was beaten on volume only by the Mercedes GLS. The back of the Audi did a curtsey on request to make loading easier. The keyfob could be a bit too keen to pop the tailgate open.
Even now Audi’s full Virtual Cockpit still startles with its clarity and versatility, although it was a pity that the one in the SQ7 (and maybe other Audis) forgot your settings when the engine was turned off. The voice recognition wasn’t great either, though it was improved in later versions. Both Android Auto and Apple CarPlay were catered for but the infotainment system running through an old-looking 8.3-inch centre screen could freeze. Lesser Audis received better info-tech ahead of the Q models. Even when it was running correctly on the SQ7, the MMI touchpad interface wasn’t massively admired. The ‘smart’ cruise control system had an unnerving inclination to flirt you back up to 70mph when you’d asked it to stick to a lower speed through roadworks.
By way of compensation, the optional Bose (or Bang & Olufsen) 3D surround sound systems were genuinely awe-inspiring, although some of the cabin buttons looked cheap. The central transmission tunnel meant that the bod sitting in the centre of the middle row had to adopt a knees-up position, ideally not booting the hell out of the big central console that housed the vents and controls for that zone’s climate control.
PH VERDICT
If, in the 2010s, you wanted a used mega-diesel hauler with more pulling power than a Thames tugboat your options were limited. In 2009 Volkswagen put out a TV ad showing its 5.0 V10 TDI Touareg towing a jumbo jet but in reality it only had 407lb ft and its chassis was mediocre.
The 2008-12 738lb ft Q7 V12 TDI was a different kettle of fish but it is now incredibly rare. Only twenty or so remain registered in the UK. A 2010 66,000-miler was sold for £23k in October 2021, but any that are available today will be a lot more than that. The only one we found for sale in the UK in September 2023 was a 125,000-mile 2011 car at £42,995.
Thankfully the SQ7 is a lot less rare. It was about half the price of the identically-platformed Bentley Bentayga, so there are plenty of sensibly priced examples on the used market. It may not have the jaw-dropping top trumpery of the V12 but in every other area, it’s a superior machine, a wonderfully capable piece of kit that manages to combine ground-chewing torque with impressive fuel economy and less of the ‘look at me’ Sturm und Drang showiness of some often more expensive, but also often less powerful, rivals. It’s a fabulous long-haul tool.
It’s also a complicated machine, not just in the electronic department which can throw up problems for just about any modern car but also in the hard engine bits, for example the two turbos, two DPFs, two EGRs, the electronic compressor etc. It’s by no means unique in its complexity but hooking into a comprehensive warranty still seems like a sensible move. Having said that, there’s evidence online of strong reliability. If you go here the comments by PHers reflect favourably on this aspect of ownership, but, of course, nobody knows what size the bills might be like in the years to come.
Although much of the initial shock and awe at the size and subjective ugliness of the SQ7 (and the Q7) has been dissipated over time by the overall enlargement of cars, in isolation these Audis are still very large vehicles. You really need to consider the sort of roads you typically drive on before taking the plunge. If you can tick that box and you have a big family and big loads to tow it could be a fine solution. If not you might prefer 3.0 TDI Q7 or, as a fully paid-up PHer, an RS6. Otherwise, a Vorsprung SQ7 will do everything you want apart from fit down a narrow alley and give you all the toys you could ever want.
The most affordable SQ7 TDI on PH Classifieds at the time of writing was this Sepang Blue 2017 example with 132,000 miles up at £32,995. For around £500 more you could snip the best part of 30,000 miles off that in this Tofana White specimen with Bose sound, full black leather and V-spoke alloys. Throw another £500 into the pot and your miles would come down to 71,000 in this first-year black-on-black car (again with Bose) at £33,980. There’s actually plenty of choice of mid-mileage cars in PH’s ‘up to £40k’ bracket, but if you prefer to spend a little more to get the miles right down £44,450 will buy this all-black 26,000-mile 2018 car with Bose and the pano roof. At the top of the price heap you’re looking at just short of £68k for this 15,000-mile ’19 MHEV mild hybrid with Bose.
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