Cooling Problems 2006 3.0DI Patrol

HI Sorry I m new to the forum and New to Patrols wondering if anyone can help with any advice? My Patrol has started to overheat the bottom rad hose seems cool when running. Ive replaced the thermostat but no difference at idle and upto 2000 rpm the car sits midway on the temp indicator once you take it for a drive if pushed unto 3000rpm temp starts to climb. theres no heat coming out of the blowers am I dealing with a bleed problem or could it be the water pump. theres no signs of water in the oil or oil in the water and car drives with no loss of power. any help or advice would be grateful
thanks

3 Litre Di's don't typically have cooling system problems - they are pretty good in that regard, so there must be something there.

Take the radiator cap off, and start the engine - once the thermostat has opened, you should see flow start to occur which will then rule out the pump as a problem.

I would be looking at blocked radiator cores, or something like that as a primary cause.

I forgot to add, you shouldn't have water / coolant coming out the top of the radiator doing this when everything is OK.

X2... the 3 litre Rads are humungous and normally have minimal overheating issues.

When they do it is usually (say 90% of the time) due to sludge and/or blocked radiator core.
A professional radiator service normally solves the problem

Note that the radiator cap is solid i.e. it doesn't open. The pressure cap is in the header tank where you normally fill.

someone tapped the back of their water jacket in the head and ran a line straight back to the head tank on the radiator...hasnt had any trouble since...sounds like a bit of work though.
Poor design seems to be the main problem with 3.0l

@romawhite did you ever solve this overheating issue??