change motor

Won't work, a smaller engine may hurt because it will take more power to move the vehicle. Leave it as it is or trade it.

I wouldn't go smaller as you will end up straining the smaller motor making it strugle to push it along, in doing that you may use just as much fuil any way. If its a petrol you could put it on gas, if its a diesel fitting a turbo and setting the fuel right will actualy make it use less fuel and have more power. It all depends on how much you want to spend to save on fuel!

go gas or 5L v8 :)

If your just looking for more efficiency I wouldn't look at replacement just yet. There are heaps of things you can do to the 4.2 to get the running costs down (and replacing with a smaller engine would not work as you would have to wring it's neck to actually get any performance out of it anyway, remember, Patrols are fairly weighty, pushing all that steel around you need something of fair size). To me, options are (if you haven't already done these) as follows: - Service- Quality Oils (this does make a difference) - What's the Compression like? When I cracked the head on my old GQ 4.2, when I replaced it, the compression improved and so did the economy - LPG? - Free flow Exhaust, don't go over 2 and 3/4" - K&N (or similar) filter - Snorkel And the old things like Tyre pressures etc etc. If the above doesn't work, I was talking to a guy the other day who put a Turbo on his 4.2 Petrol (EFI) with an Intercooler, he was amazed by the improvement in the economy of the thing (and the improved power). The bottom end of the 4.2 is REALLY Strong and can handle some good boost pressure. His SWB 4.2 would do wheel stands when he took off in 1st so the power improvement is impressive! I would think that the above mods, done correctly, would pretty much cost AS MUCH as a proparly done engine conversion (once buying a decent new engine is taken into account) but if you have your heart set on an engine swap, go a small block V8, it'll be more power and improved economy.

Is it petrol or diesel? Possibly a LPG conversion if on petrol, worse economy but cheaper to run overall - if diesel you can do a diesel gas conversion will give better economy and more power. Whatever you do DONT trade for a 3.0 litre diesel as they self destruct at around 100,000 - 150,000 kms. Smaller engine conversion will need to work harder and use more fuel.

I hear you get more fuel economy fitting a turbo,suppose its the same as more litres. If yours is not turbo already?

a 3.0 liter cdr? Just an idea?