Used Audi A8 (Mk4, 2018-date) buyer’s guide: luxury car is a second-hand bargain

Verdict

It should be cause for celebration that you can buy one of the world’s best luxury cars for less than a new supermini. And if you have a decent contingency fund, we wouldn’t dissuade you from doing so. That’s the key; you can’t buy a luxury saloon and expect supermini running costs, although fuel bills needn’t be high, nor road tax, once your Audi A8 is no longer subject to the VED supplement. Expect to pay plenty for maintenance if you cover a fair number of miles, but you’ll have one of the most complete, comfortable and refined luxury cars, which will make every journey a breeze.

Audi’s first luxury saloon was the V8, launched in 1988 and axed five years later. It failed to capture the imagination of buyers, so when its replacement was unveiled in 1994, it needed to sell in far bigger numbers. 

Audi pulled out all the stops to produce something truly different, and its aluminium-bodied A8 was just the thing. Lighter than its rivals, and so more efficient and better to drive, the A8 was much more successful than its V8 predecessor had been. 

As you’d expect, the A8 Mk2 of 2002 was even better, and the 2009 Mk3 brought further improvements. By the time the Mk4 appeared six years ago, the A8 was one of the most well rounded luxury saloons that you could buy, and further upgrades since have made it even more likeable.

History

The fourth-generation A8 reached UK roads in early 2018 with 3.0-litre V6 petrol (55 TFSI) or diesel (50 TDI) engines offering 282bhp and 335bhp respectively; the TDI came in standard or long-wheelbase forms. 

Both featured mild-hybrid tech for better economy; for those wanting more performance, the 563bhp S8 went on sale in summer 2019. Not long after, the range was bolstered by the 60 TFSI e plug-in hybrid, which also came with two wheelbases. 

A facelifted A8 appeared in March 2022 with an updated design inside and out, extra driver-assistance systems (up to 40 were available, including options), and an upgraded infotainment system.

On the road

The aluminium construction really shows when you drive the A8; every version can do 0-62mph in less than six seconds and it’s particularly agile for such a large car. As standard, all A8s came with adaptive air suspension for greater ride comfort, four-wheel steering for improved agility, and four-wheel drive for better traction. Cars on 20-inch wheels can suffer from an unsettled ride, though, so we’d opt for 18 or 19-inch items instead.

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Which should I buy?

Most of the A8s you’ll find for sale are standard-wheelbase diesels, and that’s all you need in terms of performance, comfort and luxury. Plug-in hybrids are still very costly to buy, but with one of these you could slash your fuel bills if you drive largely in town and you can charge at home. 

All A8s are luxurious, but the options list was extensive, so it’s worth pinning down the exact spec of any potential purchase. 

Standard on all were LED headlights, electrically adjustable and heated front seats, dual touchscreens, navigation, digital instrumentation, a 10-speaker hi-fi, adaptive cruise control and numerous parking aids. Long-wheelbase cars had four-zone climate control and heated rear seats with controls for the infotainment.

Alternatives to the Audi A8

The A8’s toughest adversary is the Mercedes S-Class. Crammed with tech, the Mercedes is more comfy than the Audi, but the seventh-generation car that arrived in 2020 isn’t the unassailable class leader that it once was. The other key rival is the BMW 7 Series, which was launched in Mk7 form in 2022. If you can see past its highly controversial styling, you’ll be impressed by the ride, handling, performance and quality. 

A less obvious rival is the Maserati Quattroporte, which looks great and is fun to drive, but is now dated. The Lexus LS is rare and disappointing dynamically, but very refined and comfy. Or there’s the Bentley Flying Spur, which has a fabulous interior but is very expensive to buy and run.

What to look for

Crash repairs

The A8’s aluminium construction means it needs specialist repairs after a crash. Make sure any work has been done properly.

Taxing times

Road tax is costly because until an A8’s sixth birthday you’ll pay the £410 ‘luxury tax’ on top of the standard £190 annual fee. Only the earliest cars aren’t subject to this.

Peace of mind

The standard warranty ran for three years or 60,000 miles. This could be extended to five years and 90,000 miles, with the extra-cost cover transferable between owners.

Extras, extras

A8 buyers could spend plenty on options, including laser headlights, a panoramic glass roof, electrically adjustable rear seats, massaging seats all round and way more. Check the exact spec of any purchase.

Interior

Audi makes some of the most hi-tech interiors in the industry, and its flagship saloon can feel like the Starship Enterprise at times, such is the wealth of readouts and switches. The firm has admittedly simplified things compared with the A8 Mk3, but there are still three large digital displays, including the instruments. 

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The seats are fabulously comfortable, the hi-fi sounds superb (especially with the Bang & Olufsen upgrade), and there’s masses of space for four or five adults. Buy a long-wheelbase model, which is 130mm longer, and you have genuine limousine-like comfort and space. Boot capacity is good at 505 litres, but the plug-in hybrid has to sacrifice 100 litres to accommodate the battery pack.

Running costs

There are two service schedules for the A8: fixed or variable. The former requires an oil change every 9,300 miles or 12 months, the latter allows up to two years and 18,600 miles between services, which alternate between Oil change and Inspection, at £388 and £610 respectively; from the car’s third birthday, the former price drops to £285. 

The car’s brake fluid needs to be replaced every two years at £60, but all A8 engines are chain-driven so there are no cambelts to replace. Insurance groups range between 44 (50 TDI) and 50 (the S8 and most plug-in hybrids), while fuel economy is pegged at 45-50mpg for the diesels and 30-35mpg for the petrol models.

Recalls

Audi has issued eight recalls so far, most for suspension glitches. The first came in April 2018 because of faulty head restraints, and seat rails led to a recall in July 2019. In the meantime a recall had been issued in February 2019 due to sub-standard front shock absorber forks; the rear forks were recalled in February 2020 for the same reason. 

Transmission oil leaks led to a recall in May 2020, while rear suspension problems led to further recalls in June 2021 and February 2022. Faulty front suspension links were behind a recall in July 2024. All A8s built up to February 2021 have been affected by at least one recall, but very few later cars have needed attention.

Driver Power owner satisfaction

The A8 doesn’t sell in big enough numbers to appear in our Driver Power New Car surveys, but even Audi’s more popular models don’t always figure. This year three were included, the best of which was the A5 Mk2, which finished38th out of 50. Last year there were just two, while in the 2024 Brands survey Audi came a very poor 27th out of 32, making it the worst-performing premium maker in the survey.

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