2021 (21) Audi A4 35 TDI S Line 5dr S Tronic

By Jonathan Crouch

Introduction

Here, we look at the thoroughly updated version of Audi's fifth generation B9-series A4 Avant that arrived in 2019. This featured a sharper look and still claimed to be class-leadingly hi-tech and, yes, practical. It was also more efficient thanks to the adoption of Audi's latest mild hybrid engine tech. Out back, there's a 510-litre boot that's bigger than you might expect from a car in the mid-sized executive market segment. And of course there's the usual cool, classy Audi ambience. You'd like one. Let's check it out as a used buy.

History

It's hard to be successful in the compact executive market sector without a credible estate body style - ask Jaguar or Lexus. That is, after all, what an increasing number of buyers in this segment want. Back in 2019, Audi reckoned to have nailed exactly what they needed with this car, this improved version of the fifth generation A4 Avant. This 'B9'-series A4 Avant was first launched in 2015, then substantially updated four years on to create the revised model we're going to look at here. Buyers had been able to choose the A4 in both saloon and Avant estate guises ever since this model line was first launched back in 1994 and this improved model was made sleeker and cleverer than ever before. Which was important given this car's need to face down direct competitors who by 2019 had absolutely transformed themselves - namely the Mercedes C-Class Estate and the BMW 3 Series Touring. Quite a lot's was new with this facelifted B9-era design. If you're familiar with an original 2015-era B9 A4 Avant model, the styling updates might look quite superficial but actually, only the roof, bonnet and boot lid remained the same as before. Of more significance was the fact that Audi had introduced RDE-1-compliant powerplants and its MHEV mild hybrid engine technology across the range, with a 12-volt system for mainstream models and a 48-volt set-up for the S4 TDI diesel variant. Plus on all versions, the cabin gained a new larger MMI infotainment screen to work in concert with the now-standard 'Virtual Cockpit' digital instrument cluster. There was also more equipment, a revised range structure and some of Audi's choiciest camera-driven safety and autonomous driving technology. These changes just about sustained the A4 Avant model line to the end of its life in 2024, when it was replaced by an Avant estate model range badged 'A5'.

What You Get

It's always difficult to update someone else's work, but Audi Head of design Marc Lichte addressed the task purposefully with this facelifted version of the 'B9'-series fifth generation A4, leaving only the roof, the bonnet and the boot lid of Wolfgang Egger's original shape untouched. The previous car was classy, but there was nothing particularly memorable about it. The Avant versions of this updated model have a bit more pavement presence. As ever though with an Audi, it's the interior that'll really sell you this car. In many ways, this remains the defining interior of its class from its era, with cabin quality that's still un-bettered in this segment and the cool, classy feel that's distinctive to this Ingolstadt brand. The key change here as part of this update was the addition of a much larger 10.1-inch centre-dash infotainment screen, with more sophisticated graphics, acoustic touch functionality and 'natural language voice control'. Unfortunately, that meant the deletion of the useful rotary controller that had operated the previous MMI system, but navigation's was added as standard, as were a wider range of cutting-edge 'Audi connect' media features and standard 'Apple CarPlay'/'Android Auto' smartphone-mirroring. You're positioned almost faultlessly on supportive heated seats in front of the best digital dash in the segment from this era, the 12.3-inch 'Audi Virtual Cockpit' screen, which from 2019 was fitted as standard throughout the range. Wherever you look, touch or feel, there are treats. Buttons click nicely, column stalks feel good and the low-rent plastics you'd find further down in most premium rivals are noticeable by their absence. And in the back? Well in comparison to previous generation A4s, Audi improved the rear passenger compartment of the original version of this fifth generation model by lengthening the wheelbase by 12mm, freeing up 23mm more legroom but that was still only just enough for a tall adult to sit behind an equally lofty driver - and wouldn't be were it not for the scalloped front seat backs. As for luggage space, well Avant estate models got a standard electrically-operated tailgate and with both body styles, the optional 'Advanced Key' package allows you to open either the boot lid or the hatch by waving your foot below the bumper, should you be approaching your A4 laden down with bags. This car's tailgate rises to reveal a 505-litre boot - 25-litres more than the saloon.

What to Look For

Most owners in our survey seemed happy. We've heard of gearbox problems, seat backrest faults and suspension issues, so check all these on your test drive. The steering rack can experience electrical and mechanical failure and might be noisy too. The most reported faults related to interior trim and non-engine electricals. Look out for bodywork scrapes and kerb damage to the large alloys. We've had some reports of issues with wear to the side bolsters of the leather seats, as well as squeaking front brake pads, so it's worth looking out for both of those. There were a few issues with the car's infotainment system, with phones not connecting properly and flickering screens being the main problem. Rattling parcel shelves and buzzing interior trims were also reported. The DSG automatic gearbox should be checked to make sure it's had a regular oil and filter change, as should the quattro four-wheel-drive system. Many A4 Avants will have been company or lease cars and, as a result, you should check the condition of the bodywork carefully. The high-quality fit and finish of an A4 also makes it an ideal candidate for clocking, so ensure the history is absolutely verified. As for manufacturer recalls on the A4, well some A4 models built in March 2019 may have problems with a shock absorber fork.

Replacement Parts

(approx based on an A4 Avant 2019 30 TDI - Ex Vat - autodoc.co.uk) An oil filter costs in the £4-£15 bracket. An air filter's in the £13-£20 bracket. Front brake pads sit in the £28 to £71 bracket for a set; for a rear set, it's around £20-£43. Front brake discs sit in the £41-£78 bracket; for a rear pair, you're looking at around £40-£65. Starter motor prices vary widely - from £55-£413, depending on brand. As do costs for an alternator (anywhere in the £186=£687 bracket we found).

On the Road

In terms of what was changed here as part of this B9 model facelift, the key thing was Audi's adoption of mild hybrid engine technology almost right across the board, with a 12-volt MHEV set-up provided for virtually all the brand's four cylinder engines. Otherwise, the engineering of this MK5 A4 remained much as it had been when we first saw it back in 2015 - which meant it was still primarily a front or four-wheel drive car; in a segment dominated by rear-driven rivals. This hadn't held this Audi back too much in the past and the brand didn't expect that to be much of an issue with this facelifted fifth generation 'B9'-series model either. Potential buyers of this car tend to prioritise comfort and refinement rather than on-the-limit handling and in this form, the A4 continued to deliver impressively in both of these areas. The only real caveat here lay with the firmer Sport suspension customers had to have with the 'S line' trim level that most of them chose. Try before you buy is our advice. We mentioned the mild hybrid engine tech. The only powerplant that didn't get it was the older-tech 2.0-litre diesel unit fitted to the 40 TDI quattro derivative, a 190PS model. Otherwise, the MHEV system featured on all the four cylinder powerplants, incorporating an integrated 'BAS' belt alternator starter-generator that powered a 12-volt main electrical set-up in which a compact lithium-ion battery in the boot stored energy harvested via a 'KERS' kinetic energy recovery system. A strong seller was the entry-level A4 35 TFSI petrol variant, which in this updated form got a 150PS 2.0 TFSI unit and was (from launch) the only model in the range that could be had with a manual gearbox. In S tronic auto form, an A4 35 TFSI is capable of 42.8mpg on the WLTP combined cycle. The same 2.0 TFSI engine was offered in 190PS form in the 40 TFSI - and in 245PS guise in the 45 TFSI quattro. Diesel buyers were offered the Volkswagen Group's uprated 2.0 TDI unit in 136PS form in the base 30 TDI derivative, or in 163PS guise in the mid-range 35 TDI model many A4 customers will still want. Diesel also powered the sporting S4 model, which initially used a 347PS 3.0-litre twin turbo six cylinder unit, which had the more advanced 48-volt MHEV system and is boosted by an electric compressor. This was replaced by a 3.0-litre petrol turbo V6 in 2020.

Overall

Here's a mid-sized executive estate model created by a brand that knows its customers. The magazines might tell Audi to bring us futuristic looks and an uncompromisingly dynamic drive but Ingolstadt knows that buyers in this segment really value comfort, class and quality. All three attributes were prioritised in this lighter, more agile and more advanced facelifted B9 version of the fifth generation A4 Avant. No car is perfect though and this A4 Avant does raise a few questions. It could be even bigger at the back. And in its era, there were newer designs in the segment like BMW's 3 Series Touring with a bit more tech and showroom appeal. Other than that though, it's very thorough. Very elegant. And very Audi.