FOR whatever reason, the saying 'if it ain't broke, don't fix it' always seems to ring true. But apparently that is not good enough for the boffins at Kia, because they have given the beloved Sorento seven-seat large SUV a once over.

This updates comes just over two years into the latest model's life cycle, but increasing pressure for higher safety standards has prompted the Korean company to improve the Sorento's game. As such, a suite of DriveWise technologies have been added alongside small price rises.

At the same time, engineers have been tasked with elevating the seven-seater's ride and handling, which continues to be tuned to Australian tastes. Want more? Well, they have also set upon the interior, stretching it and adding more high-quality materials.

So, did Kia manage to spoil the previously brilliant Sorento, or has it taken the model's prowess to another level? We drive the diesel-powered GT-Line flagship to find out.

Price and equipment

Checking in at $58,990 before on-road costs, the Sorento GT-Line is $500 dearer than before. But buyers should not be deterred by the price increase as Kia has upped the ante equipment-wise.

The GT-Line picks up adaptive full-LED headlights and LED tail-lights, as well as new-look front and rear bumpers, and a dark metallic finish for its tiger-nose front grille.

Other kit includes four-lamp LED foglights, red brake callipers, sill steps, GT-Line badging, dual chrome exhaust tips, a power tailgate, power-folding side mirrors, roof rails and rear privacy glass. Our test car was finished in Clear White solid paint, which is a no-cost option.

Inside, a redesigned steering wheel, a new climate control LCD display, a larger 8.0-inch Audio Visual Navigation touchscreen infotainment system with live traffic, Apple CarPlay and Android Auto support, and four-way lumbar support for the driver seat have been added.

Furthermore, paddle shifters, satin chrome highlights, an auto-dimming rearview mirror, keyless entry and start, black leather-appointed seats, eight-way adjustable front seats with driver memory function, a panoramic sunroof, a perforated heated steering wheel, a 7.0-inch digital instrument cluster, digital radio, Bluetooth connectivity, alloy sport pedals, second-row sunshade blinds, dual-zone climate control, ventilated front seats, heated outer second-row seats and a full-size spare alloy wheel are present.

Meanwhile, an excellent 640-watt, 10-speaker Harman Kardon surround sound system replaces the former Infinity set-up. But strangely rain-sensing windscreen wipers are not standard (or optional) on the GT-Line or any other Sorento variant. Why? We have no idea. And here we were thinking the calendar had ticked over to 2018 …

Interior

It would be remiss of us to not mention the knock-out job that Kia has done with the Sorento GT-Line's cabin. The combination of additional soft-touch plastics and classy gloss-black trim elevates the model to a premium-class level. While the design itself may not be awe-inspiring, it certainly is functional – and that is probably what matters most here.

The 7.0-inch digital instrument cluster and new 8.0-inch touchscreen infotainment system are both superb, owing to their easy-to-use nature and clear, concise displays. Functionality is top-notch, offering a well-rounded digital effort. Bonus points for the new climate control LCD display – unsurprisingly it is a winner, too.

The Korean brand has also succeeded packaging-wise as the Sorento feels huge inside. A 20mm increase in length has seen luggage capacity swell to 142 litres with the rear seats upright or 1662L when the split-fold second- (40:20:40) and third (50:50) rows are stowed flat.

Storage options are scarily numerous. Specifically, the cavernous storage bin in front of the gear selector is happy to devour large items and an appropriate resting place for smartphones given it is where two 12-volt power outlets and a USB port reside. If that is not enough, then the traditional central storage bin is an abyss in its own right.

First- and second-row occupants have plenty of room, while adult-sized third-row passengers are treated to decent legroom but are hampered by limited head- and shoulderroom. Naturally, the rear-most seats are best suited to children.

Annoyingly, the electric park brake's auto-hold function needs to be activated each time the Sorento's ignition is switched on. We would appreciate it if auto hold remained active until it is deliberately turned off. But that is our sole complaint for what is an otherwise impressive interior.

Engine and transmission

Powered by a 2.2-litre turbocharged four-cylinder diesel engine, the Sorento GT-Line develops 147kW of power at 3800rpm and 441Nm of torque from 1750 to 2750rpm. In reality, these outputs translate well to the road and provide a braked towing capacity of 2000kg.

While this engine does not love to rev, it is almost always surging in its thick torque band. Despite peak power coming on stream just before redline, the powertrain can feel quite lethargic in the upper reaches. Thus, the GT-Line's best work is done between 2000 and 3000rpm.

The GT-Line uses a part-time all-wheel-drive system that sends power to all four corners via a brand-new eight-speed automatic transmission that replaces the old six-speed unit. The latter is an excellent addition to the Kia catalogue and has since been employed by the Stinger sports sedan.

Gear shifts are like a smooth criminal, effortless and unassuming. And that is the best thing about this automatic transmission, you do not even notice it … most of the time.

See, the issue here is when you roll into a corner at low speed in third (or sometimes fourth!) gear, the Sorento takes its sweet time to kick down a ratio or two. Often first may be required, but the automatic stubbornly refuses, leading to delayed progress.

Four different driving modes – Eco, Comfort, Sport and Smart – allow the driver to alter steering, engine and transmission settings on the move. Smart is a new addition and claims to switch between the other three modes depending on the current driving style.

Most of our time was spent in Comfort, which saw the Sorento waft along with ease. Sport added an edge, holding onto gears for longer, wringing out every single kilowatt and newton metre for what they were worth. Eco was uninspiring, if you are interested in that sort of thing.

During our time with the Sorento GT-Line, we averaged 10.7 litres of diesel per 100 kilometres. Comparatively, Kia claims a fuel consumption figure of 7.2L/100km and carbon dioxide emissions of 190 grams per kilometre.

While higher than the Korean car-maker's claim, our result was skewed by predominantly city-based driving during the week-long test.

Ride and handling

Kia says ride and handling were key elements of the Sorento update, and driving the GT-Line makes it apparent how well its engineers did with this Australian tune.

Employing an electrically assisted rack-mounted power steering system, which has been revised for improved feedback, the Sorento is one sweet handler.

This is particularly true at low speed as corners are carved up with minimal effort. Despite measuring in at 4800mm long, 1890mm wide and 1690mm tall with a 2780mm wheelbase, the 1985kg GT-Line does not feel that large when on the move.

However, during more dynamic driving, it does tend pitch inwards on turns and is not exactly tight, such is the life of most SUVs. Nevertheless, the Sorento is among the class leaders in this area and can conquer less-angular corners at higher speeds.

It should be noted that braking performance is rather disappointing, because the brake pedal needs to be stamped on hard and early in more extreme scenarios. The GT-Line's 320mm ventilated front and 305mm solid rear discs never seem up to the task and feel weaker than they should.

Riding on a McPherson strut front and multi-link rear suspension set-up, the Sorento's ride is supple. Bumps, potholes and uneven surfaces are dealt with confidently. Thankfully suspension travel is well sorted, meaning occupants never feel like they are riding a roller-coaster.

Passengers during our time with the GT-Line were impressed by the relatively lavish comfort offered. Even its 19-inch alloy wheels wrapped in 235/55 Nexen N Priz tyres did not spoil the serenity, dismissing the precedent set by large-diameter rims.

Safety and servicing

The Australasian New Car Assessment Program (ANCAP) awarded the Sorento a five-star safety rating in October 2017. Achieving an overall score of 36.62 out of 37 – or 99.0 per cent – the Kia model is one of the safest models currently available.

Perfect results in the side impact (16 out of 16) and pole (two out of two) crash tests were complemented by a near-perfect effort (15.62 out of 16) in the frontal offset crash test. Whiplash protection was assessed as 'good', while pedestrian protection was determined to be 'acceptable'.

Driver-assist technologies under Kia's Drive Wise banner extend to forward collision warning, autonomous emergency braking, blind-spot monitoring, front and rear parking sensors, a 360-degree camera, hill-start assist and rear cross-traffic alert, while adaptive cruise control, driver attention alert and lane-keep assist are new to the GT-Line post-update.

Other safety features include six airbags (dual front, side and curtain), anti-lock brakes with brake assist and electronic brake force distribution, stability control and traction control.

Just like all other Kia models, the Sorento comes with a seven-year/unlimited-kilometre factory warranty with seven years of capped-price servicing and roadside assist.

Under the capped-price program, the seven 12-month/15,000km service intervals range in cost from $307 to $664, averaging at $454, or a total charge of $3179 over seven years.

Verdict

The Kia Sorento was already among the class leaders prior to its latest update, particularly its fully featured GT-Line flagship sampled here. But the Korean company pushed on with an upgrade focused on safety, ride and handling. The result? Pretty good, actually.

European car-makers should be intimidated by the Sorento's classy cabin, which has been elevated with more soft-touch plastics and an upgraded touchscreen infotainment system, while luggage capacity has increased thanks to some clever body work.

Meanwhile, its 2.2-litre turbo-diesel four-cylinder powerplant is meaty, so long as it’s within the peak torque band. Combine this with the new eight-speed automatic transmission that offers seamless gear changes and you have a sure-fire winner.

If that is not enough, the Australian-tuned steering and suspension are better than before, offering a level of ride and handling that is largely unfaithful to the SUV formula. The GT-Line devours low-speed corners and unsealed roads with ease.

The negatives? Well, it is thirstier in real-world conditions than anticipated, the automatic can be hesitant to downshift, the brakes are on the weaker side and rain-sensing windscreen wipers are not even an option(!?). Other than that, the Sorento is love at first sight.

Nevertheless, a boosted list of safety and driver-assist features – which now extend to adaptive cruise control and lane-keep assist – for a $500 premium should be enough to get customers into showrooms.

We highly suggest driving the Kia Sorento GT-Line before committing to another seven-seat large SUV – it is that good.

Rivals

Hyundai Santa Fe Highlander AWD (from $57,090 before on-road costs)

The Sorento GT-Line's Korean cousin, the Hyundai Santa Fe Highlander AWD, is hard to fault due to its comfortable interior, supple ride and superb dynamics. Compromised rearward visibility and a cramped second row are its only negatives.

Mazda CX-9 Azami AWD (from $64,990 before on-road costs)

A pricier option to the Sorento GT-Line, the petrol-powered Mazda CX-9 Azami AWD is a class leader with its all-round prowess, but the lack of a diesel powertrain (accounted for by the new CX-8) is a moot point.

Toyota Kluger Grande AWD (from $69,617 before on-road costs)

Significantly dearer than the Sorento GT-Line, the Toyota Kluger Grande AWD is surprisingly manoeuvrable and hugely practical with an excellent new automatic transmission, but questions over its price and low-speed ride are prominent.