Audi A6 Mk4 overview
Range overview: petrol or diesel; manual or automatic; front- or four-wheel drive; saloon, estate or off-roading estate
Reliability: above average for class
Cost to repair: dearer than average
Most common: Audi A6 2.0 TDI 190 Ultra
Best for economy and long-distance driving: Audi A6 2.0 TDI 150 Ultra
Best for urban driving: Audi A6 1.8 TFSI
Our favourite performance version: Audi RS 6 Avant performance
The fourth-generation Audi A6, sometimes referred to as the 'C7'-generation A6, arrived in 2011 and heavily borrowed its styling influence from the larger Mk3 Audi A8, which launched in the same year. Built to compete in the mid-sized executive class, the A6 was designed to take the fight to its German rivals, the BMW 5 Series and Mercedes E-Class.
There were two main body styles available for the A6 Mk4, which were the far-more-popular four-door saloon and an Avant five-door estate. A further derivation of the Avant was a lifestyle/off-road version called the allroad quattro, which came with V6 TDI power only. Although a petrol-electric hybrid A6 Mk4 was briefly produced, it wasn't offered in Ireland and therefore all variants of this Audi will be powered by a turbocharged petrol or diesel engine, the latter representing the vast majority of used models. As with most Audis, the A6 Mk4 was either front-wheel drive or four-wheel drive (called quattro by Audi), while gearbox choices were a six-speed manual, a seven-speed S tronic dual-clutch auto or an eight-speed Tiptronic torque-converter auto.
On driving the A6 Mk4 3.0 TDI Bi-Turbo for the first time, CompleteCar.ie said: "The Bi-Turbo is quick - and not just diesel quick. Find a straight stretch of road on which to open the taps and it will hit 100km/h from standstill in 5.1 seconds before sailing along to an electronically limited top speed of 250km/h. To put that turn of pace into perspective, the twin-turbocharged, petrol-fuelled, V8-powered Audi S6 is only three tenths quicker to 100km/h than its diesel sibling. But while the 420hp S6 is marginally quicker than the Bi-Turbo in those terms, it comes nowhere near to the 6.4 litres/100km (42mpg) fuel consumption."
Engine and range options for the Audi A6 Mk4
The A6 Mk4 spent most of its time on sale in the era when diesel was the heavily prevalent fuel type for this class of car and others, and so while there were 190hp 1.8 TFSI, 252hp 2.0 TFSI and even a 3.0 V6 FSI supercharged 300hp petrol engine, you'll be very hard-pressed to find any of them on the used market, as they were not popular at all in Ireland.
Taking up the brunt of the work in the A6's engine bay, therefore, was the 2.0 TDI four-cylinder turbodiesel. It originally launched with 177hp but, by 2014, had been replaced with two disparate derivations/developments of the same motor, rated at either 150- or 190hp. Either of these could be teamed to Audi's 'Ultra' fuel-saving technology to further trim CO2 emissions and increase fuel economy and, as a result of our motor tax laws, it's the 190hp Ultra you'll most commonly find second-hand.
A larger 3.0-litre V6 TDI was a silky operator and was found in three power trims during its life. Both the 204- and 245hp versions employed a single turbocharger, while the potent 313hp models were christened 'Bi-Turbo' in earlier incarnations. The A6 allroad only came with this 3.0 TDI engine, in all three power levels, and it also gained quattro all-wheel drive as standard.
Indeed, quattro was typically reserved for the higher-powered A6s, above the 204hp TDI, but it could be specified on all models if desired. Beyond the regular line-up of engines, two performance derivatives (both quattro only) were available. The S6 employed a 4.0-litre twin-turbo V8 petrol engine rated at 420hp and 550Nm, mated to an S tronic dual-clutch gearbox, and while it was plenty quick enough (and available as both a saloon and an Avant), the ultimate 'C7' speed tag went to the RS 6, which arrived in 2013. This used an even more powerful 4.0-litre V8 with 560hp and 700Nm, necessitating the Tiptronic gearbox to handle so much torque. With wider body work and aggressive styling, the Avant-only RS 6 was hugely desirable but was surpassed by the 'performance' version in 2016, which took outputs to 605hp and 750Nm on an overboost function. With a 0-100km/h time of 3.7 seconds and a potential restricted top speed of 305km/h, the RS 6 performance was the ultimate everyday sports car.
Audi offered the A6 in familiar SE, SE Business and S line trim levels, with a Black Edition also making an appearance. All models received a generous kit list from standard, with even SE cars fitted with leather upholstery, dual-zone climate control, satnav, front and rear parking sensors, cruise control and auto lights and wipers. SE Business added various comfort toys aimed primarily at fleet users, while S line followed the usual path of enhancing the bodywork with sporty addenda, enlarging the alloys to 18-inch items, fitting sports suspension underneath and upgrading the leather to a higher-quality hide. Black Editions simply replace all the exterior brightwork with matte-black trim. It's worth noting that the A6 was given a facelift in 2015, so the later cars are more modern and more desirable - but you'll pay for that.
How much is it to tax the Audi A6 Mk4?
Refer to our Motor Road Tax Prices in Ireland Explained feature for the up-to-date cost to tax the Audi A6.
How reliable is the Audi A6 Mk4?
The Audi always performed well in reliability surveys and it's comparable to its 5 Series/E-Class rivals in terms of dependability. It also has those cars' elevated parts prices, as befits a luxury premium car of this standing, but it shouldn't be outrageously expensive to run.
There was only one official recall for the A6 Mk4 during its life, issued in April 2017 and affecting late-life production from July 18, 2016, to October 14, 2016. Audi recalled various models (A1, A4, A5, A6, A7, A8, Q5 and Q7) as a change in the production process meant the airbag and belt-tensioner igniters were manufactured without adherence to prescribed tolerances. This mean that the airbag or seatbelts might not work correctly in the event of an accident, although, as only 32 Irish cars from all of these model lines were affected, the chances of you encountering an affected A6 that wasn't remedied by an Audi dealer at the time of the 2017 recall are vanishingly small.
Beyond this, there are a few known niggles. An auxiliary heater element used in the air conditioning system of 2014-built A6s could occasionally fail, while a factory-fit towing bracket on the models with the optional tow bar may have had a faulty locking mechanism - this only affects Mk4 A6s from the very end of 2015 onwards. Last-of-the-line 2018 variants with the panoramic glass roof had an issue with the bonding agent used to keep the panels in place; check this has been rectified if you're looking at an Audi with this option fitted. Fuel leaks were reported on cars built from April 1, 2011, to April 30, 2012, and again from February 18, 2014, to September 2, 2016, but there was no official recall on this issue in Ireland. Also watch out for blocked coolant pumps on cars from 2011-2016 and reduced braking performance on A6s built from the start of 2012 until August 27, 2014, the result of a ruptured servo in the brake diaphragm.
When should I service my Audi A6 Mk4?
Generally, the A6 uses a service indicator to let its owner know when the car needs a service, though even so, an oil and filter service should be carried out at least every two years or 15,000km, whichever comes first. Every three years the brake fluid should be replaced, the cabin filter should be done every two years or 30,000km and at 60,000km it is recommended to replace the fuel filter and the automatic transmission fluid (and its oil filter, too if it's the dual-clutch gearbox). The air filter lasts 90,000km. If for some reason the car is on a fixed interval service, then the oil service is due every year or 15,000km and for the petrol engines, the spark plugs should be replaced every 90,000km or six years.
Does the Audi A6 Mk4 have a timing belt?
The TFSI petrol engines and the V6 TDI diesel all use timing chains. The 2.0 TDI diesels use timing belts and they must be changed every 210,000km, regardless of time.
Can I fit child seats and a buggy in the Audi A6 Mk4?
This is a capacious and grand car, which - although primarily designed for 'executive' use - was also cleverly thought-out to cater for families. Even the A6 saloon has a 530-litre boot with 60:40 split-folding rear seats as standard on all models, allowing its carrying capacity to rise to 995 litres with the back seats stowed away. The Avant/allroad duo were even better, holding 565 litres with all seats in play and 1,680 litres with the back row folded down. Therefore, any A6 should have no problem taking a baby buggy or collapsed pushchair in its boot.
Like most cars, the A6 has two ISOFIX child-seat mounting points in the back of the vehicle, so three ISOFIX units side-by-side isn't possible. However, as a physically big car, it has a better chance than most of getting three child seats in the second row, thanks to the three-point seatbelts in all positions. Bear in mind the quattro capabilities of the A6 family means there is a pronounced transmission tunnel where the centre-rear passenger would otherwise put their feet.
How safe is the Audi A6 Mk4?
Despite scoring a remarkably low 41 per cent for pedestrian safety during its 2011 EuroNCAP crash-testing, the Audi A6 Mk4 still picked up the full five-star overall rating thanks to its other category performances of 91 per cent for adult occupant safety, 83 per cent for child occupant safety and, tellingly, an impressive 86 per cent for safety assist systems. All A6s feature six airbags (with side-rear airbags an optional extra) and electronic stability control as standard, while its technologically advanced status (for its age) means active safety features like lane-departure warning and blind-spot monitoring were on the options list from a very early stage.
Alternatives to the Audi A6 Mk4
BMW 5 Series
BMW 5 Series F10 (2010-2017) used car buying guide
Jaguar XF
Lexus GS
Maserati Ghibli
Mercedes-Benz E-Class
Mercedes E-Class Mk4 (2009-2016) used car buying guide
Porsche Panamera
Volvo S80
Volvo S90
How much is an Audi A6 Mk4 worth?
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