Audi A6 review

Our first experience of the C9-gen A6 was in Avant form with the diesel engine, so we'll start there. In truth, it’s a little grumblier than you might expect from a diesel in a big German exec, and when the A6 Avant is fully loaded with people and their worldly belongings, the little 2.0-litre turbo has to work hard for not too much reward.

Audi quotes a 0-62mph sprint of 7.0 seconds for the diesel vs 8.3s for the petrol, but even the quicker of the two feels like it could do with more grunt, and it’s not helped by an occasionally sluggish seven-speed auto gearbox. We miss big six cylinders with superhuman torque.

Is it efficient, though?

Audi claims 53.3mpg for the Sport and S Line trims, or 50.4mpg for the big-wheeled Edition 1 that we drove. The 48-volt mild hybrid system (that Audi calls MHEV Plus) deploys a 1.7kWh battery and two electric motors. One acts as a starter generator and one sits on the back of the gearbox, so the engine can switch off when the car is coasting or running at low speeds in town or traffic.

It’s an impressive system that allows the A6 to run on electric power more often than you might imagine, and when required the diesel engine kicks in without delay. There’s regenerative braking too to get juice back into the small battery, but brake feel is still decent despite the presence of new brake-by-wire tech. In the Q5, Audi offers this mild hybrid system with the petrol engine, so we’re not entirely sure why it’s diesel only in the A6.

Anyway, on a 200-mile jaunt that included both motorway and town driving, we saw just over 40mpg in the diesel A6 Avant. Not bad, but not groundbreaking either.

What about the plug-in hybrid?

It mates a 248bhp 2.0-litre TFSI four pot with a 141bhp electric motor and 25.9kWh (20.7 net) battery for a combined total output of 295bhp/332lb ft. The 0-62mph sprint is seen off in 6.0s on to a 155mph vmax, should you ever find yourself on the autobahn.

But if you have any sense, you’ll be wanting to maximise the amount of electric running, which is almost double that of its predecessor, a claimed 64 miles in the Saloon and 63 miles in the Avant. It’s set up to run in EV mode for as long as possible and works in tandem with the nav to ensure electric power is used most efficiently. You can also set the system to operate in EV or hybrid mode – in the latter you can manually set the minimum charge level to preserve e-running for later use. Handy.

Meanwhile, paddles behind the steering wheel allow you to choose between three levels of brake regeneration, but we tended to just leave it in its auto predictive mode which works well, softening off at higher speeds and increasing around town, for example. When you are forced to use the pedal, there’s a slight dead spot at the top - but regen and friction braking are otherwise nicely balanced.

It's a pretty smart system, in truth, and in our experience all rather efficient, too. Audi claims up to 128.6mpg in the Saloon (aided by its swoopier shape), and up to 123mpg in the Avant: we saw 78mpg in day to day running, though this plummeted to 34mpg when running using the engine alone. A flat to full recharge takes around two and a half hours on an 11kW AC charger.

Is it comfortable? 

The A6’s optional air suspension is excellent at dealing with large bumps in the road even with 21in Audi Sport wheels plucked from the options list. It stays flat through corners, too. However, air is a £1,755 option even on the top-spec Edition 1 trim, and it’s only available on the quattro diesel, so you’re likely to be buying an A6 with the standard springs or the sports suspension upgrade.

The PHEV we tried was equipped with the sports suspension, which lowers the body by 20mm but does without the adaptive damping of the air suspension. Unsurprisingly it’s on the firmer side – bordering on harsh at times – though it does settle down on motorways where it wafts along happily.

Anything else I need to know?

All-wheel steering is an option and is hugely beneficial for low speed manoeuvrability, but on a flowing road the A6’s steering doesn’t offer a huge amount of feel or feedback even in its sportier modes. This is a big Audi though, and that’s often been the case in the past. The BMW 5 Series is the best car in this class to drive.