Mercedes-Benz G 400d 2021 Review

The Mercedes-Benz G 400d has been on sale in Europe since mid-2019, and early predictions of a 2020 arrival in Australia have proven wide of the mark.

A shipment has now arrived to fulfil the first wave of orders placed by Australian buyers, but any new customers face a lengthy delay – potentially more than a year – as the 2021 Mercedes-Benz G 400d follows the G 63 AMG in hitting the sidelines.

It also now remains to be seen if the 400d cops a price hike along similar lines to the G 63, which despite being unavailable has pushed up to the $330,000 mark.

For now, the G 400d is a relative bargain at the current price of $233,900 plus on-road costs.

In a well-worn blueprint also successfully employed by the Land Rover Defender, the diesel-powered G-Class is loaded with luxury equipment and technology to help distance it from more utilitarian off-road options including the Toyota LandCruiser 70 Series, Jeep Wrangler and Suzuki Jimny.

All Australian-spec G 400d models come standard with Multibeam LED headlights, 19-inch light alloy wheels, a glass sunroof, Nappa leather upholstery, seat warmers and three-zone climate control.

Infotainment is facilitated by two 12.3-inch colour display screens, accessed via Mercedes’ COMAND interface and steering-wheel mounted haptic buttons. Satellite navigation, Apple CarPlay and Android Auto, digital radio, a 15-speaker Burmester sound system and three USB ports are also included, but a head-up display and wireless phone charging are not.

The 2021 Mercedes-Benz G 400d is also compatible with the Mercedes me Connect app, allowing owners to use their phone for various vehicle functions.

From the outside, the G 400d’s luxury pretensions are heralded by a standard Stainless Steel Package that includes an exterior protective strip with black insert, side running boards and spare wheel cover, as well as chrome elements around the grille, dark tinted rear glass and metallic paint.

It ensures the more affordable G-Class is in keeping with G 63’s ‘SUV for the stars’ mantle – in other words, it’s dripping in street presence.

On the safety front, the G 400d is backed by a five-star ANCAP safety rating based on the 2019 testing protocols.

That is supported by extensive driver assist functions including autonomous emergency braking (AEB), lane keep assist, adaptive cruise control, blind spot monitoring, park assist, traffic sign recognition, a 360-degree camera and more.

The G 400d is backed by a five-year/unlimited-kilometre factory warranty, while servicing intervals are spaced across 12-month/20,000km intervals.

Mercedes-Benz Australia offers service plans spanning three years ($3350), four years ($4950) or five years ($5700).

It might not wear the AMG badge that adorns the Mercedes-AMG G 63, but there is a lot to like about the brute engine in the 2021 Mercedes-Benz G 400d.

First introduced in the S-Class in 2017, the OM656 straight-six oil-burner is billed as the most powerful Mercedes-Benz diesel ever.

The 2.9-litre inline six-cylinder turbo-diesel outputs a muscular 243kW/700Nm, and just like its application in the GLE and GLS 400d, the G-Class apportions drive to all four wheels via a nine-speed automatic transmission.

In the G 400d, the oiler consumes 9.5L/100km on the combined cycle (versus 13.1L/100km for the 430kW/850Nm 4.0-litre biturbo V8-powered G 63) and accelerates the big G-Class from 0-100km/h in 6.4 seconds (G 63: 4.5sec).

We managed 10L/100km on test, but saw as low as 9.0L/100km on a highway run.

A 100-litre fuel tank theoretically translates to a 1000km range, a calculation that is somewhat achievable in reality.

Elsewhere, the G 400d rides on a robust ladder-frame chassis and is suspended via adaptive dampers that are said to offer more control and breadth of capability than passive shock absorbers.

Independent double-wishbone suspension is utilised on the front axle, while the rear employs a rigid-axle arrangement with multi-link attachment.

A low-range transfer case, full-time four-wheel drive and three differential locks are all key requisites in the G 400’s off-road suite, while a 3.5-tonne towing capacity aligns it with other heavy-duty 4x4 off-roaders, whether wagon or utility.

With its larger-than-life exterior and rugged underpinnings, you could forgive the Mercedes-Benz G-Class for being a bit kitsch inside the cabin. Like G.I. Joe in a suit.

The reality is it is anything but.

Quality furnishings, myriad technology and a bevy of storage options all conspire to lend the 2021 Mercedes-Benz G 400d a true luxe factor that somehow goes hand-in-hand with its rugged charm.

All told, it cannot quite match the balancing act achieved by the award-winning Land Rover Defender’s interior, but it’s not a million miles away from it either.

Depressing the external door release button – annoyingly, sans keyless entry function – engages a satisfying thunk before leading you into a cosseting cabin environment offering quality metal highlights, soft contact points, thick carpet and tactile switches, prefaced by thick G-stamped rubber floor mats and scuff plates that uphold some semblance of utilitarianism.

At night, exterior puddle lights and configurable ambient lighting spruce up the ambience even more, making you feel as if you’ve unknowingly walked onto the set of a Post Malone video.

Naturally, there are some quirks for a vehicle of this stature. Those same doors require a solid slam in order to latch correctly, and hoisting yourself up into the high-set cockpit requires a little more exertion than most Mercedes-Benz owners would be accustomed to.

The interior is well resolved, though, with decent incidental storage, three USB ports dotted across the two rows of seating, and headroom for days.

Despite their umpteen menus and configurations, the two 12.3-inch screens are surprisingly user-friendly, too. Two steering wheel-mounted haptic touchpads help navigate a screen each, but can be a bit fiddly on the move.

However, the biggest criticism is levelled at the G-Wagen’s dated COMAND infotainment interface.

Basically, you get a giant dial to navigate the left-hand screen and no touch-screen capability whatsoever. It’s a bugbear, especially if you’re regularly using touch-screen centric applications like Apple CarPlay.

In any case, the svelte internals are underlined by a natural, airy feel – a virtue of the G-Wagen’s huge glasshouse areas and low-set window line.

Space is generous in the first row, while the second row is suitable for a couple of adults or kiddies in child seats: loads of headroom, moderate legroom and shoulder-room.

Rear air vents (behind the console and in the B-pillar), soft contact points and a low window line are all noteworthy inclusions if you’re regularly ferrying little ones, with two ISOFIX attachment points and three top tether points to accommodate them.

Oddly, the second-row door handles are precariously close in proximity to the seat base. Another quirk is that to get the rear seat-back to fold flat, you first have to flip the seat base forward.

With that said, the 454-litre boot area is where the G-Wagen’s boxy profile imposes the biggest compromise.

The space below the G-Wagen’s considerable glasshouse is big enough to accommodate a couple of full-size suitcases or a designer pram, but not a whole lot more.

Four tie-down points and a separate 12-volt outlet in the boot are worthwhile inclusions.

Handily, the G-Class’ boot is accessed by a large rear tailgate that is oriented in a swing-out barn door configuration. A gas strut means the door is light to operate, even with the full-size spare wheel mounted on the back.

The form-follows-function ethos of the 2021 Mercedes-Benz G 400d is best demonstrated on the road.

Even with 2.5-tonne heft at play, the G-Wagen deftly balances proven off-road wares with a high level of on-road polish, possible via clever adaptive dampers and its slick diesel inline six.

Light low-speed steering, genuine driveline refinement and an arsenal of forward, rear and overhead cameras initially conspire to make the G 400d much more approachable than you’d expect in regular conveyance.

Granted, there is a natural top-heavy leaning, but it’s much more SUV than it is truck.

Placing the G 400d through car parks is relatively straight-forward, with raised indicator lenses on the outside of the bonnet helping you gauge the vehicle’s spatial extremities. That said, the G-Wagen’s towering 1.95-metre height puts it precariously close to most supermarket car park ceilings.

The diesel engine and adaptive suspension imbue the G 400d with an incredible level of control and composure at around-town speeds. There’s little lag to speak of and virtually no unwieldly movements from its 4.86-metre frame, while a relatively fast, accurate steering rack requires only moderate inputs to navigate its considerable 13.6-metre turning circle.

The diesel engine is simply a peach. That peak 700Nm torque figure materialises from just 1200rpm to provide a smooth, seemingly boundless wave of go-forward.

The nine-speed automatic gearbox facilitates the diesel’s outputs seamlessly. Sink your foot into the accelerator and it will deftly slice back a couple of ratios before plying the ponies, or gently squeeze on the pedal and it will accommodate with a surfeit of available in-gear torque.

An electric G-Class might be on the way, but in the meantime it’s hard to think of a better performance/efficiency balance than the inline-six diesel.

Straight-line speed and control from the G-Class is only possible with a taut body. To that end, the G 400d delivers consistently strong road-holding and body control ideal for anything this side of a mountain of switchbacks.

Pitter-patter bumps are comfortably soaked up with aplomb, while larger washouts are supplanted by excellent absorption from the dampers. No big compressions, no big rebounds; it’s almost as if you’re floating over the surface, such is the level of control, noise insulation and outright nonchalance.

In a similar vein, the G 400d shifts its weight admirably to the outside wheels during corners, and resists most pitching or heaving tendencies.

Sure, physics ultimately prevails if you push it beyond the design brief, but until that point it is smooth, refined progress – underlined by an adeptly-tuned electronics and safety suite that makes most mainstream systems feel primitive by comparison.

Initially, the Land Rover Defender holds a slight edge with its level of road-holding and performance, but we’ll await a proper comparison test before delivering a final verdict.

Scope for serious off-roading with our first drive of the 2021 Mercedes-Benz G 400d was limited, however we did manage to seek out a couple of hill climbs and water crossings.

Quite simply, the G-Class took everything in its stride, with ample wheel articulation, minimum 283mm ground clearance, the low-range transfer case and those three differential locks putting paid to any obstacle – even with road-centric Pirelli Scorpion tyres fitted.

The short but worthwhile stint in the dust puts an exclamation point on the diesel G-Wagen experience.

Plenty of vehicles can take you off the map, but few do so in such cosseting comfort.

How much does the 2021 Mercedes-Benz G 400d cost?
Price: $233,900 (plus on-road costs)
Available: Now
Engine: 2.9-litre six-cylinder turbo-diesel
Output: 243kW/700Nm
Transmission: Nine-speed automatic
Fuel: 9.5L/100km (ADR Combined)
CO2: 252g/km (ADR Combined)
Safety rating: Five-star (ANCAP 2019)