Anyone who follows market trends knows that buyers are increasingly eschewing sedans in favour of SUVs, and ditching diesel-powered passenger cars at a rate of knots.
It's hard to review the upgraded 2018 Mazda 6 diesel without taking this into account, which might be why the company projects only about four per cent of buyers will go for this engine, equating to fewer than 100 sales per year at the going rate.
None of this makes the car you see here a bad offering, though, just a misunderstood one. And even though this mid-sized Mazda is nominally six years into its life cycle, running changes keep it fresh against the Toyota Camry, Holden Commodore, Volkswagen Passat et cetera.
It's interesting that Mazda hasn't carried over the old diesel engine to this MY18 model, but has instead done some reworking to make it smoother and punchier. The diesel engine is the flagship donk in the mid-level Mazda 6 Touring spec level tested here, as well as the base Sport. It sits in contrast to a $3000 cheaper 2.5-litre NA petrol engine making 140kW and 252Nm.
The twin (variable geometry) turbocharged 2.2-litre unit gets cool tech like more precise piezo injectors, a new combustion chamber holding multi-stage ignitions timed to counter knocking, new water-flow management, and rejigged coolant control.
It's very smooth for a diesel actually, with a muted clatter from outside, but very few vibrations or much noise coming through the firewall and into the cabin until you're approaching redline – which you almost never will. It's also got a muscular mid-range brought about by the familiar wave of torque, making its rolling response effortless. It's a performance diesel in the European tradition.
The resultant output gains are notable too: power's up from 129kW to 140kW, and peak torque climbs from 420Nm to 450Nm, at 2000rpm.
Matched to the engine is the familiar six-speed torque-converter automatic transmission with manual setting but no aggressive-downshift-enabling sports mode. It may lack ratios on paper, but the wider ratio spread is covered by the engine's torque, and it's never fussy or perturbed.
The elephant in the room, though, is what's available higher up the range.
The Mazda 6 Touring sedan with a diesel engine costs $39,690 before on-road costs. The more highly specified GT version can now be had with the CX-9 SUV's 170kW/420Nm turbocharged 2.5-litre petrol engine for $43,990, with snappier acceleration and even fewer vibrations inside the cabin.
The big benefit of a diesel engine is its fuel economy. Mazda claims an ADR figure of 5.3 litres per 100km on the combined cycle – about 30 per cent better than the turbo-petrol – though in urban driving that'll get closer to 7L/100km. Still very efficient, particularly on highways. That's why high-milers are well served with diesel.
It's easy to see why this version will be a niche, though if you're one of the dwindling few still drawn towards this fuel type, Mazda's effort is an exceedingly good one. We'd suggest that for most buyers, petrol will be fine – that GT turbo is particularly appealing – but for a regional buyer or oft-travelling sales rep, diesel can work.
Mazda also claims its engineers have “revisited every aspect” of the chassis, though of course this doesn’t equate to wholesale changes. The company reckons it’s now more rigid, while the tweaked single-tune suspension is a little smoother over bumps. You'll still scrape the bumper lip from time to time over bigger bumps if you're not careful.
Other detail changes apparently include body reinforcements, thicker sheet metal in the rear wheel wells and trailing link mounts, as well as extra chassis bracing and sound-deadening materials, all helping to improve NVH suppression. Quiet cars are luxury cars after all...
The electric-assisted steering has about the right amount of resistance built in, while the 6 is the first Mazda with urethane in the rear damper top mounts that's designed to take the edge off sharp inputs.
In a perfect world, we would love for Mazda to have transplanted the CX-9’s on-demand AWD system, though the diesel's characteristics negate any chance of torque steer. There’s a tendency for the car to scrub when pushed hard, despite the G-Vectoring system that cuts torque delivery to the front axle, causing a forward weight transfer ahead of a corner.
Dynamically, the Mazda remains somewhere in the middle ground for the segment: not quite as cosseting and 'long legged' as a Passat or Hyundai Sonata, but also not as stiff and terse as a performance sedan either.
So, what else is new? A lot of the really cool new features have been reserved for the range-leading GT and Atenza variations, as you can read in more detail here. We're referring to stuff such as Walnut Brown Nappa leather paired with Sen wood accents.
You'd still be hard-pressed to call the Mazda 6 Touring's spec list anything other than generous, though it's more of an everyman proposition.
There's an enlarged new 8.0-inch tablet screen controlled by touch, voice (to some degree) and the MZD Connect rotary dial, an approximation of BMW's iDrive. This is augmented by a new head-up display that projects onto the windscreen rather than a dinky flip-up piece of glass. A Mercedes-Benz C200 doesn't have that...
There's also DAB+, satellite navigation, button start with proximity key, an 11-speaker Bose audio system, dual-zone climate control, black leather seats with electric adjustment, rain-sensing wipers, LED headlights and DRLs, front and rear sensors, and 17-inch alloy wheels on 225/45 tyres.
Over the course of the Mazda's life cycle, the company has fitted a growing list of active safety features. All versions get high- and low-speed autonomous emergency braking (also available in reverse), radar-guided active cruise control, blind-spot monitoring, rear cross-traffic alert, traffic sign recognition and lane-departure warning.
The Mazda 6 has the maximum five-star ANCAP crash rating; however, given its advancing age, it was tested back in 2012 against simpler metrics. It's not clear what it'd get today, though we'd guesstimate it still holds up.
The layout is as contemporary and modern as you'd hope for. The slim ventilation controls are lovely and sit below that tablet screen. The driver's instruments are basic and analogue, but the HUD redresses this. The steering wheel is a lovely leather-clad number, and the range of seating and steering column adjustments are plentiful. The seats are also wider and more padded than before.
More importantly, the material quality and tactility are pretty premium, bordering on Lexus levels.
Apple CarPlay and Android Auto software are coming, the company says, but Mazda is being coy on when despite the tech rolling out on this car in North America. We understand it could be retrofittable to MY18 cars sold without it. We will keep pestering Mazda on this...
While the MZD Connect system impressed us when it appeared a few years ago, it's a little slow to boot up and lacks a little visual impact today. It's time for a re-skin, we think.
As ever, the back seats are not the most spacious in this class – a Ford Mondeo is a little roomier – though it’s roomier than RWD premium offerings such as the Lexus IS. That said, most adults below 180cm will have sufficient head and leg room, and all get ISOFIX anchors. There are standard rear vents and a new folding armrest with two USB points built in.
Only one-in-three buyers opt for the wagon option, but the extra practicality it affords makes it seem like a no-brainer. The sedan’s boot is a modest 474L compared to 506L for the wagon up to the retractable tonneau cover. The key, though, is the fact you have up to 1648L with the back seats folded down. The wagon also gets a cargo net, a 12V input in the rear, a spoiler, and roof rails.
From an ownership perspective, Mazda Australia has finally come to the party in offering a five-year warranty with no distance limit. Servicing costs are quite reasonable, alternating between $319 and $390 per visit, albeit at smallish 10,000km (or 12-month) intervals.
So, the verdict. To say the mid-sized sedan market is populated with a number of strong contenders is an understatement. The Mazda 6 remains one of the better offerings, despite getting on in years, and kudos to the company for its recent updates.
Does a diesel engine make sense, though? Strictly speaking, not unless you're doing a lot of miles. Of course, it's such a strong unit that we'd recommend it as the performance choice at the Touring spec level. We'd look at stretching to a GT turbo-petrol probably, but if diesel floats your boat, your VW (Passat) and Mazda dealers are two of the best places to go.