What’s in a new engine? Well, for Isuzu, quite a lot. The Japanese commercial vehicle specialist introduced its latest 1.9 litre Ddi BluePower engine for its D-Max pick-up truck in Thailand way back in 2015, but even though we’ve seen a facelift and a smattering of special editions since, the new mill has always eluded us.

That’s the problem with having lower-quality fuel than the rest of our peers, and if you recall, there was also a two-year delay for the introduction of Mitsubishi’s new-generation MIVEC engine for the Triton. But the fact of the matter is that this segment waits for no one, and plenty of new and impressive rivals have surfaced in the ensuing years.

While all this was happening, the D-Max was saddled with its outdated and underpowered 2.5 litre engine, which felt increasingly out of place next to the powerful, refined diesel mills of its competitors. That left Isuzu fighting for scraps on the table with one arm tied behind its back.

But now, after four long years, Isuzu Malaysia has finally introduced the newfangled mill, which is claimed to be more powerful, efficient and refined than before. It finally gives the truck a shot in the arm, but is it too little, too late? Don’t be fooled by the Malaysian number plates of the car you see here – we actually travelled all the way to Phuket to see what’s what.

The introduction of the new engine over here coincides with the second facelift for the long-serving second-generation D-Max, which was first seen in the Land of Smiles in 2017. Compared to the initial nip and tuck from 2016, the revisions here are more modest and are all clustered around the front of the truck.

Still finished in chrome, the large grille’s U-shaped inserts have been inverted – giving the impression of fangs – and the shiny trim now extends into the headlights as well. Speaking of which, the range-topping model you see here gets bi-LED units for the first time, while the LED daytime running lights are now L-shaped. The fog light surrounds also feature some thicker chrome trim.

You’ll also find a new 12-spoke design for the largest 18-inch alloy wheels; local models are also slathered with huge “1.9 BluePower” graphics along the sides and tailgate to make sure every bystander knows what’s under the bonnet. New colour options include Red Spinel Mica and the Sapphire Blue Mica you see here, and Isuzu is also offering an optional tailgate damper to make it easier to open and close, priced at RM650.

Inside, the changes are even more subtle. There’s now some stitched soft-touch material covering the instrument cluster hood, upper glovebox cover and door armrests, lifting the perceived quality just a touch, while semi-gloss black trim can now be found on the aforementioned glovebox cover (where you’ll also find a new “Isuzu D-Max” badge) and the surrounds for the window switches.

Elsewhere, the part-leather upholstery gets a new design and there’s also a new USB port at the rear. The Android-based infotainment system with an eight-inch touchscreen was introduced on the limited-edition X-Series last year, and while it’s not the last word in terms of operation or aesthetics, it works well enough and features the full Google Play Store and Waze built in. There’s also a reverse camera, as expected nowadays.

Otherwise, it’s the same D-Max interior you know and love. You still get the novel circular climate control interface and the Terrain Command rotary controller to switch between two-wheel drive, four-wheel drive and low range. The cabin is also still (mostly) littered with hard plastics and some unsightly finishes, yet feels like it can survive a nuclear holocaust. There’s also a decent amount of room both at the front and at the back, but as usual, the rear seat backs are far too upright for you to get comfortable on long journeys.

Safety-wise, the D-Max now gets hill descent control, joining the standard kit list that includes dual airbags, ABS with EBD and brake assist, stability control, hill start assist and ISOFIX rear child seat anchors. The returning 3.0 litre model adds six airbags, meaning that for the first time, all of the mainstream one-tonne pick-ups in Malaysia can now be had with six airbags or more.

Of course, the engine is by far and away the biggest news here. Codenamed RZ4E-TC, the new 1.9 litre common-rail direct-injected four-cylinder diesel mill replaces the old 2.5 litre 4JK1-TCX, promising increased power and torque, even greater fuel efficiency, reduced emissions and improved refinement – all the while maintaining Isuzu’s legendary reliability and durability.

The smaller displacement is said provide an ideal compromise between low friction and pumping losses, and has the added benefit of reducing weight by as much as 56 kg. To make up for the decrease in swept volume, the engine utilises a variable geometry turbocharger that works at a wider range compared to the previous unit. This, together with the higher-pressure fuel injectors, boosts power and reduces fuel consumption.

Also aiding efficiency is a piston shaped like a clothoid curve, which further promotes the mixture of fuel and air, enabling a more complete combustion. There’s also an intelligent exhaust gas recirculation (EGR) system that enables the control of combustion temperature, reducing nitrous oxide emissions.

Isuzu has also worked hard to reduce friction, adding low-tension piston rings and a diamond-like carbon (DLC) coating on the piston pins and injector needles, making the engine even more efficient and durable. Overall, the company claims an impressive 37% decrease in friction.

The result of all this is 150 PS at 3,600 rpm and 350 Nm of torque from 1,800 to 2,600 rpm, increases of 10% and 9% respectively over the 136 PS and 320 Nm of the old engine. Despite this, Isuzu claims a 19% improvement in fuel efficiency, with a combined consumption figure of eight litres per 100 km.

To ensure that the engine can handle the dramatic increase in specific output, the cast iron block is now 13% stiffer, while the longer piston skirts further increase rigidity and reduce noise. The induction-hardened cylinder bores also provide increased resistance against wear.

Serviceability has also been improved through the use of a hydraulic valve lash adjuster and a maintenance-free automatic tensioner for the accessory drive belt. A high-performance steel timing chain, now mounted at the rear of the engine, allows for a longer service life.

The lineup of transmissions have also been upgraded, with the manual and automatic options both now offering six speeds. The new gearboxes have a wider ratio spread and feature a tweaked final drive ratio to improve drivability, particularly when towing. Isuzu claims a zero-to-100 km/h acceleration time of 13.7 seconds with the automatic and 13.9 seconds with the manual, more than a second quicker than before.

Four years is a long lead time for an engine to be introduced here, but Isuzu says there’s a good reason for that. The company has spent a total of 3,500 hours bench-testing the oil burner to cope with both our lower-quality Euro 2M diesel as well as B20 biodiesel, the latter as part of an incoming government mandate. The addition of a pre-fuel filter will allow the use of local fuel, while a simple hardware fix is promised for B20.

The company has also conducted local high-altitude testing in Genting and Cameron Highlands, Kundasang and Tambunan, in order to ensure that the new D-Max will cope with hillier terrain over in Malaysia, as opposed to the relatively flatter Thailand.

It’s hard to overstate just how much more modern the new engine feels, most of which is down to its smoothness and lack of noise. That much is evident even before you set off – the old mill was fairly loud and uncouth by current standards, but at idle this new one does a remarkable job of hiding its clattery demeanour.

This carries on through when you’re mooching about in city traffic, with just a hint of gravelly noise emanating through, and it’s only when you floor the throttle do you really hear the engine groan. Even so, it’s not too loud, and doing so also reveals the extra punch from the new motor.

Sure, even with the significant increase in outputs, the numbers are still modest and lag behind the rest of the competition – you’re not going to win any traffic light grands prix with this one. Still, it offers whatever little performance it has from low down, making light work of getting you around in urban environments. Again, it’s only when you ask for more that it starts to struggle, especially at the top end.

The automatic gearbox is a bit more old-school. This isn’t one of those slick six-speeders you’ll find in most passenger cars – it’s lethargic and often takes what feels like an eternity to change gears. At least it’s smooth and, just like the previous unit, it won’t upshift in manual mode unless you do it yourself, though such a sporting characteristic is a little out of place in a vehicle like this.

Also old-school is the rest of this pick-up, which mechanically remains unchanged. The suspension continues to be softly sprung at the front, dealing with minor surface imperfections surprisingly well but allowing for far too much body movement over larger bumps, while the unsophisticated leaf springs and solid axle cause the rear end to skip about on rough roads. There’s also quite a bit of shudder coming through the ladder frame.

On a winding road, the steering’s slow gearing robs you of any sense of what the front wheels are doing, and the hefty weight takes some strong-arming in tight corners (or when parking). As expected, there’s plenty of body roll, but what isn’t so expected is how little grip the Toyo all-terrain tyres exhibit, squealing in the bends even at relatively sane speeds.

So, not the most dynamic or comfortable steer, then. But you have to remember that ride and handling was never the D-Max’s strong suit, and there are other competitors far better suited for that. Where Isuzu has always excelled is in delivering a tough, dependable workhorse, and while we haven’t had the chance to explore the full breadth of the new model’s capabilities just yet, we can expect much of the same here.

Added to that, the new engine is smoother and more responsive, and the company has expended a lot of effort into making sure it is even more reliable and durable. It also looks set to remain the efficiency champion in the segment, and while it doesn’t have the headline figures of its rivals, one must not underestimate the huge savings in road tax the smaller displacement will bring – particularly important for fleet buyers.

What’s more, Isuzu claims pricing will be “highly competitive”, so it could provide a convincing value proposition as well. Yes, if you’re looking for a pick-up truck that can double as a bearable daily driver, you might be better off looking elsewhere. But if you want it to do what it says on the tin, then the new D-Max with its much improved engine is worthy of your consideration.

The facelifted 2019 Isuzu D-Max has been launched in Malaysia. Pricing ranges from RM80,149 for the double cab 1.9 litre 4×2 Low Ride manual all the way to RM120,838 for the double cab 3.0 litre 4×4 Premium automatic. The unit you see here is the double cab 1.9 litre 4×4 Premium automatic, priced at RM115,799.