Great, I explicitly mentioned a diesel and the replies I got were about petrol engines. In these applications I prefer diesel for the range, torque, and durability which no doubt you are familiar with as well.
I don't doubt it's coming, but the road to certification in the US is long and expensive, thanks to Volkswagen and FCA and others. It's gonna be a while. It's my experience that dealers will take a deposit on an interstellar time-traveling spaceship if you give them a check.
In any case, expect Ingenium gassers first. JLR more broadly is stinging from their approach to diesels in Europe and the rapidly declining demand there where diesels made up over 90% of JLR sales. The utter lack of any kind of news regarding a six-cylinder turbodiesel Ingenium, plus the switch in Europe to the non-Ingenium SDV6 from the Td6 for MY 2019 seems to indicate they are either struggling with certification or struggling with other issues related to customer expectations and demand, or both. FWIW I hope we get it in the US.
The good news is the D5's engine bay was designed from the start to accept the longer inline-6 block. Pic attached - that's mine, and that's about 10+" of space between the front of the block and the radiator. It's practically mid-front-engined. The Defender is based on the same modular architecture so it's reasonable to expect the Defender will get the inline 6's as well - at least for the 110 which should have similar external dimensions to the Discovery.
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