It's worth checking the fan is connected the right way round!
Mine had been re-connected the wrong way after a refresh last year and was blowing instead of sucking and showed the same symptoms as yours.
I have no issues with temps other than over-cooling and I usually need to tape up half the nose at about 15 deg C ambient temps.
This is running with a standard radtec rad, 11" Spal fan here IIRC, 82 deg drilled thermostat, dry sumped with oil cooler.