My 4.8 runs cool in hot weather and quite hot in cold weather.
It's around 90 when very hot (I had a month in Provence this year which was very hot) and around 100 when it's cold.
Too much hysteresis in the coolant temperature control. There have been similar issues when more efficient after market aluminium radiators are fitted, actually increasing engine temp under certain motorway conditions. Cure I believe was an alternate thermostat.
Note not all thermostats of same quoted temperature are equal. I had an overheating issue with a boat diesel engine cured by a higher temp thermostat because it started opening 14°C below its listed temp.
