While one publication wrote that the Wrangler would get the same V6 diesel as the Grand Cherokee and Ram 1500, other sources have claimed the traditional VM four-cylinder diesel would return, in 2.5 or 2.8 liter form.

2018 Jeep Wrangler rendering

Which shall it be, and will Americans see one?

There are good and bad points for each. As Bob Sheaves wrote, the V6 poses a distinct packaging problem, due to the extremely high pressure fuel lines being in the crash path, and interference with the power brake system. These can be addressed, but at a cost. On the lighter side, the VM diesel is reliable, economical, powerful, smooth, and already in use in the United States by FCA, meaning that there is somewhat less risk, mechanics already have training and tools, and there is already an inventory of parts.

Traditionally, Eurojeeps have been fitted with VM four-cylinder engines , in recent years the 200 hp, 302-339 lb-ft 2.8 liter variety.  This provides a good deal of grunt (less horsepower, more torque than the gasoline six), but currently doesn’t meet American or future-European emissions. Except when it does — in GM’s Duramax form.

VM 2.8 liter diesel (2006)

 

At least one Allpar member has pointed out that the 2.8 is being redesigned yet again, to match Euro 6 and United States emissions standards (which are coming closer together).  The redesign will likely include a small power boost, but is mainly being done to meet emissions rules. Since the 2.8 has been used for a good many years in the Wrangler anyway, it’s been packaged already, and while it means a slightly longer engine bay (to fit that one extra cylinder), it also means much more space on the sides.

Then there are VM 2.5 liter diesels being discussed; closely based on the 2.8, it will reportedly get a power boost. Chrysler has used both engines.

Finally, there is VM’s new L424 engine , a 2.4 liter, which was to have nearly 200 hp and 368 lb-ft of torque. When last seen, it had solenoid-based direct injection to reduce emissions to US ULEV standards.

The main disadvantages of the four-cylinder diesels are relatively low horsepower and not being already tuned for US use — again, inventory and training are absent, for the moment. However, they could be used in smaller vehicles here, in place of the Fiat Multijet diesels (minivans and other SUVs, for example). Fiat owns VM, so from a corporate view, it's six of one and half a dozen of the others, assuming they can boost production.  One advantage of the 2.5 and 2.8 is presumably lower cost and weight.

At this point, there has not been any official word on whether the American Wrangler will get any diesel, and it is likely that a diesel option would be a late arrival.