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Audi A6 S-Line 3.0 TDI Avant

The A6 is one of the oldest models in Audi's line-up, but its strong diesel engine and four-wheel drive grip still make it a contender.

As it’s one of the oldest cars in Audi’s line-up, you could be forgiven for looking past the A6. But don’t ignore it. 

A facelift in 2008 assures the car a place at the executive class top table, while the blend of quality, practicality and performance makes the Avant estate model a force to be reckoned with.

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A mid-life refresh has helped fend off the car’s advancing years, as the flush-fitting surfaces and neat proportions ensure the Avant looks just as modern as the younger Mercedes. And the trademark Audi grille gives it an imposing presence.

This impression is aided by our car’s S line trim. It features head-turning additions, such as fashionable LED running lights, lowered suspension, redesigned bumpers and side skirts, plus handsome 18-inch alloys. As a result, it stands out from lesser SE models and ranks alongside its rivals here for kerb appeal. 

Modern Audi cabins enjoy a reputation for quality and clarity – and that is down to the success of cars like the A6. It helped set the template and still looks good today, with soft-touch materials and a simple design set off by classy detailing and brilliant build quality. Only a few pieces of older switchgear reveal its age and the wraparound dash, tall transmission tunnel and S line seats enhance its sporty appeal.

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Used - available now

A6

2021 Audi

A6

20,681 milesAutomaticDiesel2.0L

Cash £26,099
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A6

2021 Audi

A6

63,560 milesAutomaticDiesel2.0L

Cash £20,495
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A6

2021 Audi

A6

34,657 milesAutomaticPetrol2.0L

Cash £21,000
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A6

2023 Audi

A6

23,882 milesAutomaticPetrol2.0L

Cash £29,400
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The brand’s tried and tested MMI cabin control system remains easy to use and more instantly intuitive than either of the rival set-ups on display here. Up front, the seats are comfortable and easy to adjust, while rear passengers get plenty of legroom. Light window tints and thin windscreen pillars also make the Audi feel roomier than either rival. 

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But while the Avant is a match for the Touring on boot space, both cars trail the E-Class for ultimate capacity. The A6 is also the only car without a flat boot floor when the rear bench is stowed, although we like the simple load divider and its wipe-clean plastic undertray.

All three cars deliver similar power outputs, but the A6 has 40Nm less torque, at 500Nm, and a slower-shifting six-speed box. So it was no surprise that the car trailed in our 0-60mph tests, with a time of 7.7 seconds. Then again, the quattro 4WD came into its own in the wet, and ensured this was the most composed model off the line.

The extra traction is also evident in corners; the Avant is incredibly capable and inspires confidence on greasy surfaces. It’s just not as much fun as the rear-driven BMW in the dry. 

The A6 scores on refinement. Its 3.0-litre engine is quiet and smooth, while the linear power delivery makes for relaxing and deceptively quick progress. The lowered S line suspension means the car feels nimble for its size, with less body roll than in the BMW or Mercedes. It crashes into potholes, while the steering doesn’t provide enough feedback, but this old timer is still a strong choice.

Details

Chart position: 3WHY: The old-timer in this test, but the A6 Avant is still very desirable – especially in swift 3.0-litre TDI quattro guise...

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