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S6 TDI Quattro Black Edition 4dr Tip Auto
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By Jonathan Crouch
By 2019, there had been more powerful Audi S6 models in the Ingolstadt brand's history, but never one boasting as much as 700Nm of pulling power. This fifth generation C8-series Audi S6, introduced in 2019, got that courtesy of a torque-rich V6 TDI engine. For the first time in an S6, there was diesel power - and it was the only option. Audi promised that this black pump-fuelled unit would fully deliver on the promise of the red rhombus-backed S badge. Let's check this car out as a used buy.
4dr saloon / 5dr Avant Estate (3.0 TDI diesel)
By the end of this century's second decade, while Audi's RS models had been getting progressively more powerful, some of its 'S'-badged sporting models had been going in the opposite direction. Take the S6. The third generation C6 model which sold between 2004 and 2011 had a Lamborghini Gallardo-derived petrol V10 developing a massive 429hp. That was replaced in 2012 by a 414hp petrol V8 in the fourth generation C7-series model. Seven years later, this fifth generation C8-series car arrived with an output of 'just' 350hp. But the major change was that it was fitted with a diesel engine - a very impressively-specified 3.0-litre V6 TDI one. Don't worry: there are compensations. Pulling power with this C8-series S6 rose hugely despite the power output drop - from 550 to a massive 700Nm. So this S6 should prove as quick as its badge suggests it ought to be. Sales started in 2019, with an update in 2023. The car sold until the end of 2024.
You won't be considering an Audi S6 if you want to shout about your performance pretensions. This car doesn't do that. In fact, over the years, it's got the whole business of not doing that down to a fine art. A lot of it's in the detail. Audi S cars have a reputation for styling subtlety and whether you order it as a saloon or an Avant estate, this one is no exception. The silver horizontal lower splitter creates an enormous feeling of width at the front, linking the two air inlets and ending with the two winglets at the air ducts. As with other A6 variants, piercing LED headlamps flank the wide Singleframe grille. Side-on, you'll notice the big 20-inch wheels with their 'S'-specific design. And perhaps also the wide sills and the silver door mirror casings. At the rear, the S6 features an integrated spoiler that visually extends the boot lid. A diffuser insert in dark chrome matt adds the finishing touch to the lower rear end. The four tailpipe trims are in gleaming chrome. The cabin is as well appointed as you'd expect from a range-topping A6 model, with beautiful monogrammed leather sports seats, and an S-specific graphic layout for the standard-fit Audi Virtual Cockpit instrument binnacle digital display which features a central rev counter. The back seat offers reasonable space for three adults, but much more comfortable room for two and you get a fold down centre armrest with storage and cup holders. Out back, in the saloon model there's a 530-litre boot; if that's not enough, the alternative Avant estate variant gives you 565-litres.
Please contact us for an exact up-to-date valuation.
Not too much goes wrong with a C8-era S6. The 3.0 TDI diesel can also suffer from high oil consumption and with this unit, we've also heard of DPF clogging, EGR valve malfunctions, turbocharger failures and timing belt wear. The most reported C8-era S6 faults relate to interior trim and non-engine electricals. We've had some reports of issues with wear to the side bolsters of the leather seats, as well as squeaking front brake pads, so it's worth looking out for both of those. There were a few issues with the car's infotainment system, with phones not connecting properly and flickering screens being the main problem. The DSG automatic gearbox should be checked to make sure it's had a regular oil and filter change, as should the quattro four-wheel-drive system. Many S6 models will have been company or lease cars and, as a result, you should check the condition of the bodywork carefully. The high-quality fit and finish of an S6 also makes it an ideal candidate for clocking, so ensure the history is absolutely verified. If the S6 you're looking at has a panoramic glass roof and was an early C8-era model, be aware that on a few cars, this roof became unstuck from its frame.
(approx based on an S6 TDI (2019) - Ex Vat) An air filter costs in the £84 bracket. An oil filter costs around £6. A fuel filter is around £27. Front brake pads sit in the £58 to £91 bracket for a set; for a rear set, it's around £25. Front brake discs sit in the £51 bracket; for a rear pair, you're looking at around £77-£186. A headlamp is in the £968-£1,170 bracket; and a wiper blade is in the £11-£19 bracket.
The 3.0-litre V6 TDI engine used here with its electrically-powered compressor is basically the unit originally introduced in Audi's SQ7 large SUV, but was embellished here with a 48-volt electrical mild hybrid set-up, which took the powerplant's total power output to 350hp. All of those braked horses are transmitted via an eight-speed tiptronic automatic transmission to the car's quattro all-wheel-drive system. The electrically powered compressor is the major reason for this S6 model's startling performance. 62mph from rest takes just 5.0s in the saloon model - which is virtually the same as was achieved by the far more powerful 4.0-litre petrol V8 of the previous generation version. And you get that performance here with far more pulling power in this C8-era design thanks to dual supercharging that sees the electrically powered compressor working in tandem with the exhaust turbocharger and producing 700Nm of torque.
It's tempting to dismiss this C8-era S6 on a number of grounds. For Audi owners, it's not as agile as an S4 that would save you plenty. And it's not as fast as the kind of RS 6 that wouldn't cost that much more. And that's before you even start to think about the talented opposition. But as soon as you do, you begin to realise that within its little market niche, this car is something quite special. It's also a very clever contender indeed. Over 35 miles to the gallon from a car that, de-restricted, would probably reach well over 180mph? And at the same time, pulling power that would embarrass most of this model's powerful petrol-engined rivals. So what if an RS6 from this era is faster? Or an M5 or an E63 come to that. This, in contrast, is the stealth bomber of the executive segment, the car that creeps in under the radar. The only one in its sector with diesel drive. And the only one with Audi's S-inspired ring of confidence. Four rings in fact.
Data provided by CAP-HPI database - Ref# 103295
By Jonathan Crouch
By 2019, there had been more powerful Audi S6 models in the Ingolstadt brand's history, but never one boasting as much as 700Nm of pulling power. This fifth generation C8-series Audi S6, introduced in 2019, got that courtesy of a torque-rich V6 TDI engine. For the first time in an S6, there was diesel power - and it was the only option. Audi promised that this black pump-fuelled unit would fully deliver on the promise of the red rhombus-backed S badge. Let's check this car out as a used buy.
4dr saloon / 5dr Avant Estate (3.0 TDI diesel)
By the end of this century's second decade, while Audi's RS models had been getting progressively more powerful, some of its 'S'-badged sporting models had been going in the opposite direction. Take the S6. The third generation C6 model which sold between 2004 and 2011 had a Lamborghini Gallardo-derived petrol V10 developing a massive 429hp. That was replaced in 2012 by a 414hp petrol V8 in the fourth generation C7-series model. Seven years later, this fifth generation C8-series car arrived with an output of 'just' 350hp. But the major change was that it was fitted with a diesel engine - a very impressively-specified 3.0-litre V6 TDI one. Don't worry: there are compensations. Pulling power with this C8-series S6 rose hugely despite the power output drop - from 550 to a massive 700Nm. So this S6 should prove as quick as its badge suggests it ought to be. Sales started in 2019, with an update in 2023. The car sold until the end of 2024.
You won't be considering an Audi S6 if you want to shout about your performance pretensions. This car doesn't do that. In fact, over the years, it's got the whole business of not doing that down to a fine art. A lot of it's in the detail. Audi S cars have a reputation for styling subtlety and whether you order it as a saloon or an Avant estate, this one is no exception. The silver horizontal lower splitter creates an enormous feeling of width at the front, linking the two air inlets and ending with the two winglets at the air ducts. As with other A6 variants, piercing LED headlamps flank the wide Singleframe grille. Side-on, you'll notice the big 20-inch wheels with their 'S'-specific design. And perhaps also the wide sills and the silver door mirror casings. At the rear, the S6 features an integrated spoiler that visually extends the boot lid. A diffuser insert in dark chrome matt adds the finishing touch to the lower rear end. The four tailpipe trims are in gleaming chrome. The cabin is as well appointed as you'd expect from a range-topping A6 model, with beautiful monogrammed leather sports seats, and an S-specific graphic layout for the standard-fit Audi Virtual Cockpit instrument binnacle digital display which features a central rev counter. The back seat offers reasonable space for three adults, but much more comfortable room for two and you get a fold down centre armrest with storage and cup holders. Out back, in the saloon model there's a 530-litre boot; if that's not enough, the alternative Avant estate variant gives you 565-litres.
Please contact us for an exact up-to-date valuation.
Not too much goes wrong with a C8-era S6. The 3.0 TDI diesel can also suffer from high oil consumption and with this unit, we've also heard of DPF clogging, EGR valve malfunctions, turbocharger failures and timing belt wear. The most reported C8-era S6 faults relate to interior trim and non-engine electricals. We've had some reports of issues with wear to the side bolsters of the leather seats, as well as squeaking front brake pads, so it's worth looking out for both of those. There were a few issues with the car's infotainment system, with phones not connecting properly and flickering screens being the main problem. The DSG automatic gearbox should be checked to make sure it's had a regular oil and filter change, as should the quattro four-wheel-drive system. Many S6 models will have been company or lease cars and, as a result, you should check the condition of the bodywork carefully. The high-quality fit and finish of an S6 also makes it an ideal candidate for clocking, so ensure the history is absolutely verified. If the S6 you're looking at has a panoramic glass roof and was an early C8-era model, be aware that on a few cars, this roof became unstuck from its frame.
(approx based on an S6 TDI (2019) - Ex Vat) An air filter costs in the £84 bracket. An oil filter costs around £6. A fuel filter is around £27. Front brake pads sit in the £58 to £91 bracket for a set; for a rear set, it's around £25. Front brake discs sit in the £51 bracket; for a rear pair, you're looking at around £77-£186. A headlamp is in the £968-£1,170 bracket; and a wiper blade is in the £11-£19 bracket.
The 3.0-litre V6 TDI engine used here with its electrically-powered compressor is basically the unit originally introduced in Audi's SQ7 large SUV, but was embellished here with a 48-volt electrical mild hybrid set-up, which took the powerplant's total power output to 350hp. All of those braked horses are transmitted via an eight-speed tiptronic automatic transmission to the car's quattro all-wheel-drive system. The electrically powered compressor is the major reason for this S6 model's startling performance. 62mph from rest takes just 5.0s in the saloon model - which is virtually the same as was achieved by the far more powerful 4.0-litre petrol V8 of the previous generation version. And you get that performance here with far more pulling power in this C8-era design thanks to dual supercharging that sees the electrically powered compressor working in tandem with the exhaust turbocharger and producing 700Nm of torque.
It's tempting to dismiss this C8-era S6 on a number of grounds. For Audi owners, it's not as agile as an S4 that would save you plenty. And it's not as fast as the kind of RS 6 that wouldn't cost that much more. And that's before you even start to think about the talented opposition. But as soon as you do, you begin to realise that within its little market niche, this car is something quite special. It's also a very clever contender indeed. Over 35 miles to the gallon from a car that, de-restricted, would probably reach well over 180mph? And at the same time, pulling power that would embarrass most of this model's powerful petrol-engined rivals. So what if an RS6 from this era is faster? Or an M5 or an E63 come to that. This, in contrast, is the stealth bomber of the executive segment, the car that creeps in under the radar. The only one in its sector with diesel drive. And the only one with Audi's S-inspired ring of confidence. Four rings in fact.
