The end of a legendary engine? 2025 Isuzu D-Max and MU-X to get new 2.2-litre turbo-diesel in Thailand to fight Toyota HiLux and Ford Ranger but what does it mean for Isuzu 4JJ3's future in Australia?

At long last, Isuzu’s Thailand division has confirmed rumours that the brand will launch a new smaller diesel engine for its two-strong 4x4 line-up.

The new unit, a 2.2-litre turbo diesel engine dubbed MaxForce, is an up-sized version of the 1.9-litre (RZ4E-TC) engine the brand launched in 2019.

According to media across South East Asia, the new up-sized engine will also receive a new turbocharger and is designed to be “more powerful” and “faster” than current engines. Power figures are yet to be revealed. For reference, the current 1.9-litre engine produces 110kW/350Nm, while the 3.0-litre 4JJ3-TCX produces 140kW/450Nm.

In a comment to CarsGuide Isuzu Ute Australia said it was “not in a position to comment on future product plans” but that it was “monitoring reception to the news to ensure any product updates to our local range meet the unique requirements of our local market before introducing any change locally.”

The brand pointed out that the version of the 4JJ3 engine deployed locally is unique to Australian specifications with some upgraded hardware to better suit our market.

A Thai-based teaser confirms the new engine will be deployed on both the D-Max ute and MU-X SUV. Currently the brand’s Thai website is offering sign-ups to test drive both vehicles with the new powerplant.

But in a line-up which already has a low-power and high-power option — why is Isuzu overseas splitting the difference with this new 2.2-litre unit?

2025 Isuzu D-Max MaxForce teaser

The answer lies in emissions regulations, not just here in Australia — Isuzu’s largest export market — but in its manufacturing base and largest market of Thailand.

Recent developments in Thailand have the country’s National Environment Board introducing Euro 6 equivalent standards for internal combustion engines, starting January 1 of 2025.

Isuzu will get some reprieve, at least initially, as the Environment Board has stopped short of including diesel engines in its emissions crackdown due to an overarching economic slowdown in the Thai vehicle market, over concerns that requiring AdBlue to further reduce diesel engine emissions would lead to mass layoffs in the industry.

However, it seems with even South East Asia now looking to cut emissions in a big way, older and larger displacement engines will need to be replaced by more efficient options.

2025 Isuzu D-Max MHEV

Again, the figures tell the story. The current 1.9-litre RZ4E engine consumes 6.9L/100km of diesel on the combined cycle (in a D-Max SX), and emits 180g/km of C02, while the 3.0-litre 4JJ3 consumes 8.0L/100km and emits 207g/km (in a D-Max X-Terrain).

Both vehicles will pass the first round of Australia’s NVES laws without attracting fines. For “Type 2” (ladder-frame) based vehicles, this is 210g/km in 2025, however, only the 1.9-litre passes the next phase, which in 2026 shrinks to 180g/km. Isuzu can continue to sell the 3.0-litre engine after this date, but if the fleet average falls over the mandated number, it will begin to attract penalties in 2027.

Isuzu will no doubt need to encourage buyers into 1.9-litre vehicles or, alternatively, it can avoid the fines by selling sufficient numbers of its upcoming zero-emissions electric D-Max.

If Isuzu can’t do either, it will need to absorb the financial penalties, pass them onto consumers, or discontinue the 3.0-litre engine as an option in its line-up.

2025 Isuzu D-Max MHEV

The 2.2-litre engine could be the potential replacement, and emissions for its 1.9-litre relation can also be improved on thanks to the existence of a mild hybrid (MHEV) option in Thailand (revealed last month) which offers no improvement on power, but a further reduction in emissions thanks to a small electric motor and 48-volt electrics. It is entirely possible the new 2.2-litre unit will ship with MHEV tech from the beginning.

If it arrives in Australia, the 2.2-litre engine will go into battle against Kia’s new 2.2-litre Tasman (154kW/441Nm), as well as both its Thai-built rivals, the 2.8-litre MHEV HiLux (150kW/500Nm), and the 2.4-litre twin-turbo Triton (150kW/470Nm).

However unlike Kia, Mitsubishi, and Toyota, the new NVES environment is more challenging for Isuzu, which does not have a line-up of hybrids and lower-emissions petrol vehicles to help it reduce its fleet average.