Outer Limits 4x4 Board

Anyone got any ideas...my terrano keeps getting hot under load (towing, steep hills) runs ultra cool around town, about half on the highway. Has new thermostat, water pump, radiator, clutch fan hub is all good, uses no oil or water (both are clean)...I'm out of ideas. Its a 98 manual td

Mate i think these engines are a 4 cylinder version of the TD42 6cyl in the patrols ?? if so go to patrol4x4 forum and check out the artical in the GU secton about the TD42 overheating issues and some mods to thermotats etc its a big read good luck