Overheating 2003 GU Patrol 3.0L

I will second that, you most likely have one blocked radiator.

I'll third it. Mine did the same after re-build and the radiator was blocked so flushed and new top tank and all has been good for last 4 years. Cost $500!
It will appear that the radiator is fine by it will have reduced cooling capacity, due to the blockage, and will only reveal itself under load. The 3-0 cooling system is pretty good, hence the ability for travel, with light loads, with the blockage. Take it to a radiator specialist.

As I elaborated in a previous thread, while the pin is still in the grenade they are an excellent vehicle. When I first picked mine up we were living in the Pilbara and just to see how good the cooling system was we sat on 130km/h for an hour or so going from Karratha to Paraburdoo on a day when the mercury was around 47 C in the shade, temperature gauge did not move.

But about 12 months ago the pin fell out and I had poured many thousands in to the blakchole under the bonnet, until I finally had enough 4 months ago and traded it.

Cheers

Snowy

Snowy,
I am well aware of the pins working loose as mine did about 4 years ago! They are an excellent vehicle with the weak links being the engine, perhaps the gearbox (in my model), the disfunctional electronic fuelling system and the support from the Nissan Motor Company ! I am not a fan of Nissans (especially the Nissan Motor Company) even though I own one, but a lot of other vehicles also have a "black hole" which devours $100 notes at an astonishing rate. Anyway if we weren't meant to spend money, they wouldn't make it!!!!
Standard temperature guages quickly get to the operating zone and rarely fluctuate unless they are near boiling or boiling so the fact that yours did not move does not mean that the temperature did not rise. If the guages rose up and down to indicate true coolant temperature, we'd all be nervous wrecks!
I got 195,000 out of the first engine! Second one has done about 50,000 so I reckon (hope) I have about 100,000 to play with.