There's a particular type of used car purchase that represents exceptional value — where the original buyer absorbed steep depreciation so that the second or third owner can have the same car for a fraction of what it cost new. The executive saloon class is where this works most reliably, and the Audi A6 is one of the best examples of it. A car that cost £50,000+ new loses half its value inside five years, which means a well-maintained 2019 A6 with full Audi service history is available for £25,000–£30,000 — the same amount as a new mainstream family hatchback, but with significantly more space, specification, and presence.
This guide deals specifically with the two generations of A6 most buyers should consider: the C7 (2011–2018) and the C8 (2018 onwards). The older C5 generation (2005–2011) is now old enough to warrant significant caution on any car without a comprehensive documented history and recent major maintenance, and is outside the scope of a guide aimed at buyers spending their money wisely.
C7 or C8?
The C7 A6 (2011–2018, with a facelift in 2014) is the generation where the used value is most compelling. Well-maintained examples from 2015–2018 can be found in the £16,000–£25,000 range, and for that money you get a genuinely spacious, well-built executive saloon with a strong specification. The C7's interior is good by the standards of its era — though it doesn't match the digital-heavy interior of the C8 — and the engines, particularly the 2.0 TDI and 3.0 TDI diesels, are well-proven at this point after millions of road miles.
The concerns with the C7 relate to its age rather than any specific generation failure: a car from 2015 is now ten or eleven years old, and the service and maintenance history matters more as a proportion of the purchase decision than on a newer car. Any C7 without documented service history requires more caution. Any C7 with evidence of deferred maintenance requires factoring in catch-up costs. A clean-history C7 from a reputable seller remains a compelling buy; a history-light C7 at a very low price is a different calculation.
The C8 A6 (2018 onwards) is the current generation and the one where early lease returns are now producing genuine used value. The C8's interior is a step forward over the C7 — twin touchscreens replace most of the physical buttons, the optional virtual cockpit digital instruments are excellent, and the build quality is at the highest level Audi has achieved in this class. The C8's mild-hybrid technology on diesel models improves economy and refinement. A 2019–2021 C8 A6 in SE trim with the 40 TDI (2.0-litre diesel) represents one of the most car-for-money propositions in its class on the used market.
Which engine?
The A6 has been sold with a wide range of petrols and diesels. For most buyers, the diesels make most sense — executive saloon buyers typically cover higher annual mileages, and the diesel's economy advantage on motorway runs justifies the engine choice in a way it doesn't in a city supermini.
The 2.0 TDI (190PS on C7 post-facelift, 204PS as the 40 TDI on C8) is the volume diesel and the right choice for most buyers. It doesn't have the seamless, effortless torque of the 3.0 TDI, but it's notably quieter than older diesel generations, economical on longer runs (50–60mpg is achievable on motorways), and at this point well-proven in terms of reliability. The C8's 40 TDI with the mild-hybrid system is particularly refined — there's a stop-start smoothness that the C7's diesel doesn't quite match. On any 2.0 TDI, the standard diesel concerns apply: check for DPF history on any car with a predominantly urban service record.
The 3.0 TDI (218PS to 349PS depending on year and tune) is the engine that defines what the A6 is at its best. The torque delivery — 620Nm on the 286PS version, for example — makes the A6 feel effortless in a way that the 2.0 TDI doesn't quite manage. At motorway speeds it's one of the most relaxed ways to cover distance, with economy figures of 45–50mpg achievable on a genuine long run. The cost premium for 3.0 TDI models on the used market is real but has compressed to a reasonable level on C7 examples. On any 3.0 TDI with significant mileage, the injectors are worth checking — high-mileage common rail diesels can develop injector wear that's expensive to address. Ask for any documented injector work on any example over 150,000 miles.
The 2.0 TFSI petrol is the petrol choice for buyers who do predominantly local mileage or have strong feelings about diesel. In 190PS or 245PS form on the C7, it's a smooth, capable petrol that doesn't have the same cost justification as the diesel for high-mileage buyers but serves perfectly well for those covering 10,000 miles or less per year.
Avant Estate vs Saloon
The A6 is available in both saloon and Avant estate bodystyles. The Avant is the more practical choice — the estate boot is 565 litres versus the saloon's 530 litres, and the load area is significantly more accessible. The Avant holds its value slightly better and is often preferable for family use. The saloon has cleaner aesthetics if boot practicality isn't a priority. Both are widely available on the used market; the Avant commands a small premium that's usually worth paying for buyers who need the space.
Which trim level?
SE is the entry point and already well-equipped on C8 models — the standard specification includes the 10.1-inch MMI touchscreen, virtual cockpit, three-zone climate control, and the adaptive cruise control. For most buyers, SE represents complete specification.
Sport and S Line add sportier styling elements and, on S Line, firmer suspension. The ride on S Line models on UK roads deserves a specific test drive — the standard suspension setup is more comfortable, and the visual difference of S Line isn't always worth the ride trade-off.
Vorsprung is the top specification — massage front seats, head-up display, panoramic sunroof, matrix LED headlights, and a comprehensive suite of driver assistance. These compress well in value on the used market and are worth seeking out for buyers who want a fully-equipped car.
What goes wrong?
MMI infotainment on C7 cars. The third-generation MMI system in the C7 A6 can be slow to respond and occasionally freeze, particularly on pre-facelift cars from 2011–2014. Software updates at service visits improve stability but the older system doesn't match the responsiveness of the C8's touchscreen setup. Test it specifically during viewing.
Air suspension on higher-spec C7 and C8 models. The adaptive air suspension option — standard on some specifications, optional on others — can develop leaks from the air struts as the rubber diaphragms age. The symptom is a car that sits unevenly at the front or rear, or that noticeably sags overnight. Air suspension replacement is expensive (£500–£1,200 per corner). On any A6 with air suspension, watch the car settle after sitting stationary for ten minutes and look for any unevenness in ride height.
DSG/S tronic service interval on all automatic A6s. The same guidance as the A3: confirm that the DSG/S tronic has been serviced at 40,000-mile intervals. Ask for the specific DSG service record, not just the general service book.
Timing chain on 2.0 TDI C7 (pre-2015). Earlier 2.0 TDI engines in the C7 used a timing chain arrangement that can develop noise on extended high-mileage cars. The symptom is a rattle from the engine on cold start. On any pre-facelift C7 2.0 TDI over 120,000 miles, this is worth checking.
What you should actually pay
- C7 2.0 TDI SE (2014–2017): £13,000–£20,000
- C7 3.0 TDI S Line (2015–2018): £18,000–£26,000
- C8 40 TDI SE (2018–2021): £24,000–£33,000
- C8 50 TDI S Line (2019–2022): £30,000–£42,000
- C8 Vorsprung (2019–2022): £35,000–£48,000
The depreciation on executive saloons makes the A6 genuinely compelling value on the used market. A C8 A6 that cost £55,000 new in 2019 is now available for under £30,000 with full service history and reasonable mileage. That is the economic reality of buying in this class used rather than new.
Before you see it
HPI check is essential — finance is very common on executive saloons and any unresolved finance registers against the car, not the person who arranged it. Check the service history for DSG service records and confirm the oil change intervals have been maintained. On C7 cars with air suspension, ask the seller to confirm the ride height is even before you arrive.
Check the MOT history before you go →
Free MOT checker at AllCarsUKRegistration plate only. Every test, advisory, and mileage. Free, no account needed.
On the test drive: park the car for ten minutes and observe whether it sits evenly (air suspension). Test the DSG at low speed. Start the diesel from cold and listen for any chain rattle before the engine reaches temperature. Drive at motorway speeds — the A6's natural habitat — to confirm the refinement level is as it should be. At 70mph in a well-maintained A6, you should hear almost nothing.
Should you buy one?
A 2019–2021 C8 A6 Avant or saloon in SE trim, 40 TDI, S tronic (the 7-speed wet DCT), Vorsprung or SE specification, full Audi or Audi-approved service history: one of the most car-per-pound purchases available in its class. The A6 does something that mainstream alternatives don't — it wraps you in space, quality, and refinement without asking you to notice the effort. That's what executive cars are for, and at used prices the A6 does it for what a new mainstream hatchback would cost. The service costs are higher than a Passat, but if you buy the right car, the total ownership experience justifies the expense.
Specifically: find an independent Audi specialist for servicing rather than a main dealer. The service cost difference is significant, the quality of work is comparable, and the availability of well-priced genuine-spec parts means the ownership economics of the A6 make more sense than the new-car service pricing suggests. That's true for the A4 as well, but the A6's higher service costs make the differential more meaningful.
Also see: BMW 5 Series Buying Guide | Audi A4 Buying Guide | Skoda Superb Buying Guide