i have noticed this scenario also(hilux,patrol,jackaroo) and im wondering if its more fuel temperature.hop out and feel tank when level is low and tanks are often warm,cold fuel runs so much better(imho)
I have had pretty good fuel economy out out both my CRD Patrols.
I was a little nervous going to the new one, just in case it wasn't going to be as good, but they have both showed nearly identical fuel use, with the same driver ( me )
Mic
I took delivery of my GU8 about a month ago. So far all driving has been around town with air con on with out side temps usually around 40c. I average 11.9 L/per100. I expect that to improve a little once the engine/drive train has had a bit of time to free up a bit. I reckon thats pretty good for such a big vehicle....
My GU8 im getting 16L/100km with a snorkel and not towing anything and can't get it any lower than that.
We bought our '06 ex Telstra 4.2 with 150,000kms for $31k. It had had a hard life but had been regularly serviced with replacement rather than repair when necessary. It also came ready fitted out with the necessities for remote travel.
Our plans are similar to yours - long term ownership & around Australia travel.
The two reasons we decided to go with the 4.2 Patrol.
1. It's reputation for longevity (motor & transmission).
2. When wanting to hire a 4wd for exploring the Dampier Peninsula from Broome, the only vehicles that any of the many hire companies would allow to go up there were Landcruisers & Patrols. They had a variety of other 4wd's for hire, but reckoned that whilst capable they just didn't hold together as well over time. This told us something about the relative 'toughness' of these vehicles compared to others. We couldn't afford the extra to buy a Toyota.
The 4.2 is quite heavy on fuel.
It also gets left at the lights by the 3.0 litre models ..... but will cruise happily at 90kph to 110kph, with plenty left for overtaking. And let's face it , long term travel around the country is not a race. Our average cruising speed in our Nissan Civilian bus when travelling around the country was 80kph, with a max of 105kph (downhill, wind behind us!). This was only ever an issue on busy roads, & we'd pull over to let traffic pass if it built up behind us, but most of Australia's roads our slowness was never an issue. When we got the Patrol it felt like a relative speed machine! :-)
Hope this might help in your decision making, but whatever you end up getting, you,ll find folks driving just about every sort of vehicle imaginable out there 'on the road' & having a ball doing it.
Cuppa
Some up to date figures.... My wife just did a round trip to Kings Canyon from the Alice. All bitumen. 40c outside and the aircon on. It is a return trip of 900klms. Lets call it 950klms to include a little extra running around. She left town with full main (145litres) and sub (30litres). There were 6 people in the car and it was fairly gusty (windy). She sat on 120khp for the vast majority of the trip, 130 at times.
I just put 150 litres in to refill it. That makes approx 15.8 L / 100klms. I still think that the 3 litre is returning good figures. I reckon that if the speed was brought back to 100/110 it would return about 12l / 100klms....