Outer Limits 4x4 Board

My gq 4.2 diesel is getting hot while towing and only while towing. If we go out 4bingwith usual hill climbs, soft stuff etc no probs sits just under 1/4. But last trip to LCMP towing a bloody heavy camper trailer( not mine ) i noticed it getting hot to the point that it was about to hit the top of the gauge so we pulled over and with just idling started to cool down to about 1/2 so we kept going.Then on the weekend was towing a car trailer for a mate a couple of trips with cars on the trailer noticed the temp got up to 1/2. So main Q is this fairly normal or could there be a problem

Cheers

Mine doesnt seem to get hot normally even when towing with A/C on, but recently it started getting hot doing slow uphill 4wding, or even uphill driving for a period of time. ie just below the second top line. I removed and tested the thermostat and noticed it wasnt opening till the water started to boil. Replaced it and its running fine again.

How old is your radiator and how long since you had it flushed ?

not sure how old radiator is and ive not done a flush since ive owned it (about 8 months) and i will take thermostat out on weekend and see how it is

cheers

Spend 20mins pull the radiator out. TD42's are piss easy to do. Take the cowl off. Hose out the fins on the radiator then stick hose in engine bay and clean out the A/C thingy.
Then put it all back together.

to really clean the radiator the header tank has to come off and a brush run through the cores.