prado 2008 diesel radiator temperature

Yes that is normal.

If your radiator is not considerably cooler at the bottom than the top it is not doing it's job.

remember hot in the top cold out of the bottom.

Bare in mind also many of the modern vehicles will not get hot enough to open their thermostat just sitting idling ...... so there will only be a very small flow ..... like a piddle thru the radiator until the engine gets hot enough to open the thermostat.

So the bottom of your radiator may be stone cold

cheers

AS mentioned above the radiator should be cold or as near to it as is possible in the ambient temp. It can't be less than ambient temp.

If your rad stay cool for much of it's height then the system is working well. Unfortunately engine load creates heat and MORE cooling is required,so the rad may get hotter further down.
If the vehicle is an auto, then the auto dumps heat into the bottom of the rad to cool the auto.
With all working hard and auto adding heat + the engine adding more than normal may get the rad bottom to a fairly high temp. When the rad cannot dissipate heat quickly enough the system then over heat.

A temp gauge in the bottom of the rad is a very good indicator of how close you are to the overheat/boil runaway situation where steam appears. Most don't have such temp sensing and rely on a water temp gauge which sort of does the job ok.