Review and road test of the Isuzu D-MAX [RT] (2017 - 2020)
By Jonathan Crouch
The Isuzu D-Max has traditionally been the kind of pick-up you'd choose if you wanted one not afraid to put a bit of serious dirt beneath its wheels. The 'RT'-series model was launched in 2012, but here, we look at the version updated with a down-sized 1.9-litre diesel engine, launched in 2017. How does it fare as a used buy?
1.9 Pick-up (diesel)
Isuzu knew back in 2017 that at first glance, long-time D-Max owners might have a few qualms about switching to this revised version of the 'RT'-series model, a design which by then had been in production for five years. After all, there weren't too many visual changes and the old 2.5-litre diesel engine had been replaced by a down-sized 1.9-litre unit with less pulling power than before. Take a second glance though and the appeal of this much improved package starts to become more obvious. The engine puts out 164bhp, which is virtually the same before, and the small torque deficit was compensated for with revised gearing, which is why this truck's 3.5-tonne towing capacity remained un-bettered in the class.
As you'd expect, the 1.9-litre powerplant is far cleaner and more economic than its predecessor. Plus its considerably lighter weight also allows for a useful 50kg payload increase across the range and enables this Isuzu to be driven without the major road speed restrictions which now apply to some of its heavier rivals. Of course, the improvements to his model weren't all about the engine. Buyers also got the option of an updated 6-speed automatic gearbox, slightly smarter looks, a re-designed cabin, stronger standards of safety and a more complete equipment tally, especially when it came to media connectivity. In this form, the 'RT'-series model sold until it was replaced by an all-new 'RG'-series design in 2021.
What You Get
Styling hasn't been a priority for Isuzu pick-ups in the past that offered rugged, squarical shapes, big wheels, lots of chrome - and not a lot else. The original version of this 'RT'-series D-Max model moved that philosophy forward a little, with a rather more appealing design originally developed in the wind tunnel of the Japan Railway Research Institute, the place where the famous Bullet Train was born. This shape was further refined here.
Most of the changes took place at the front, where the bumper and the bonnet were revised, as has the imposing grille that separates re-styled headlights incorporating LED daytime running lights. There are smarter front fog lamps too.
Behind the wheel, in terms of the interior changes made to this revised D-Max model, the instrument panel was re-designed with an updated central display and clearer fonts for the instruments. Infotainment's was also upgraded for this improved model. Avoid the entry-level variants and you get a 7-inch multi-function touchscreen, upgraded in size to 9-inches on the flagship 'Blade' derivative. For rear-seated folk, there's slightly more passenger comfort than is provided by some rival models, thanks to this Isuzu's relatively long wheelbase. This facilitates head, shoulder and leg room and allows the seat back to be less vertically inclined, for greater comfort on longer journeys. One nice touch is the way that 60/40 split-folding rear seat base enables you to more flexibly use this rear passenger space for packages, should you so wish.
Time for a few practicalities. Drop down the sturdy tailgate and the headline news is the size of the cargo bay. There's 1,485mm of load bay length in the Double Cab model, a figure that rises to 1,795mm in the Extended Cab bodystyle and 2,305mm with the Single Cab body shape. All variants offer 1,530mm of load bay width and 465mm of load bay depth. That of course makes this area easily big enough for a euro pallet, which can slide in the 1,110mm-wide space between the wheel arches. That might encourage you to carry heavier loads, so it's important that the total payload capacity is usefully high, rated at around the 1.1-tonne mark.
What to Look For
There's certainly stuff to look for here: one of the things about buying a used D-Max is that it's more likely than some other models in this segment to have been seriously used off road - or for really heavy loads. We came across a number of issues with our ownership survey.
Like lots of other pick-ups featuring independent front suspension, this Isuzu can experience a very short front CV joint life. The wear and tear associated with big wheel articulation, big tyres, plus ingress from water and dirt can contaminate the joint, and you can be getting through front CVs at an alarming rate.
The best advice is to replace these like any other service item and not have to worry too much. But you can also keep an eye and an ear on them by listening for the give-away clicking and clacking of a worn CV when doing a U-turn or any turn on full-lock. Of course, by then, the joint will be already shot. Make sure the rubber boots are also kept in good shape; even the smallest nick or split in the rubber means the end for the CV within. A lot of people using this Isuzu for heavy work have found that the standard suspension needs a bit of an upgrade to cope - upgrade kits are available on the after-market.
Some owners have reported that this vehicle's auto gearbox can get hot when using the vehicle hard. There's a transmission-temperature warning light that will illuminate, but like most warning lights, the damage is often done by the time the light comes on. You can conceivably drive around this problem. Don't let the vehicle select a too-high gear on a twisting uphill road. Manually pull it back a gear, allowing the engine to get into its comfort zone and the torque converter to slip less, thereby producing less heat. Also, keep an eye on things in the long term. Check the colour and smell of your transmission fluid. If it's black and has a burned smell, it's probably cooked and should be replaced.
(approx based on a 2018 D-Max - Ex Vat) An oil filter is in the £28 bracket. Front brake pads cost in the £84 bracket. Front brake discs cost in the £186 bracket. A wiper blade is around £26. An air filter is around £35. A rear brake light bulb is around £7.50.
On the Road
In this improved D-Max, the venerable old 2.5-litre diesel engine that would take you through almost anything was discarded in favour of a down-sized 1.9-litre unit. Though this powerplant puts out 164PS - virtually the same as its predecessor - it develops 40Nm less torque, the total figure having slipped from 400 to 360Nm. To try and compensate, Isuzu changed the gearing ratios - there's a very short throw between first and second gear and that helped to maintain the previous model's impressive towing ability: 4x4 versions of this truck will still pull along up to 3.5-tonnes.
There's a choice of either a 6-speed manual gearbox or a redesigned 6-speed automatic transmission. Whichever of the two set-ups you select, there are certainly plenty of gearing choices, with a set of high range ratios you can use in either for two and four-wheel drive and a low range transmission option for the really mucky stuff. As you'd expect, the smaller, lighter engine improves running cost efficiency. A 4WD manual Double Cab D-Max model can return up to 40.4mpg on the combined cycle and 183g/km of CO2 (both NEDC figures).
If you thought Isuzu pick-ups were a bit rough and ready, you might be pleasantly surprised by this updated 'RT'-series post-2017 model D-Max. Once, this brand was really one reserved for the requirements of pure commercial operators. In this form though, it could even suit private buyers looking for an all-terrain utility vehicle that can play the lifestyle card.
But how does it stack up against obvious rivals from the 2017-2020 era? Very well actually. This is, after all, by a small margin the most practical pick-up in the class from this period in terms of the size and weight of things it can carry. It's one of the few models that's light enough to avoid highway speed limitations. And experience would suggest that no other pick-up will prove to be more rugged, should you continually subject it to serious off road use. As a result, you can see why so many professional choose this Isuzu. In a marketplace full of pretenders, it's that rarest of things: the genuine article.
Isuzu D-MAX [RT] (2017 - 2020) review by Jonathan Crouch