[Stocker]

Agree with MikeC's post above. Also agree that 210 is a bit higher than I'd like to see, but as you said, the system was being torture tested. How hot does it run during normal use? Also, do those electric fans have any shrouding? Lastly, it's possible that 165 t-stat might be doing more harm than good. If coolant circulates too quickly, it doesn't spend enough time in the radiator to transfer as much heat as it could with, say, a 190 or 195 t-stat.