GU 3.0 Auto - engine overheating

Hi Guys,
I'm having engine overheating problems when towing. It only has got hot when towing for about an hour or so and when there is a hill or rise. The radiator has been replaced before I bought the car, the fan pumps plenty of air, A/C thermo fan works OK, there are no external leaks and is not using any coolant.
I have been told that it may be the auto trans cooler transferring excess heat through the radiator causing the engine to overheat.
The car shows 300k but not sure if it has original engine or auto.
I would like to know if there is a common problem and if there is a solution.
Cheers

Gday,

any chance on some more detail such as year, temps it gets to, do you tow in overdrive etc. Mine goes up to 93-94 on a bad day so I back off a little. I'm guessing yours is a tad worse. Don't want to sound rude but how sure are you the radiator was replaced & who did it ?

Have a look at this thread in the meantime.

Its an 02 model. I've had it for about 7-8 months. Done mainly highway driving with no dramas until I started towing the camper trailer (1200kg). I have tried driving with overdrive off and it did seem to improve but it still heats up when running uphill.
It only has original temp gauge in dash and got into the H section of gauge the first time, and I back off when i see it start to climb off its normal position.
As for the radiator, it has a sticker of the repairer on it and does look to be pretty new, the core/fins are in good condition, other than that I only have the sellers word.

Hey Drew,

I just read through that thread of Goat's, and I think it would be pretty wise to have the radiator removed and checked out.
It looked OK like mine does, but you just can't know from the outside.

Thanks mate

put in a oem(original )thermostat dont use aftermarket ones they play up
can be the cause of many an overheating problem