[ecomodded]

I forgot.. the fan was just on mid speed as your not nearing the upper temperature limit, I checked and upper temp with out boil over is 230-240* on a hot day say towing a load or up a hill etc.
I am pretty sure a hot running motor would be thinning and cooking its oil.
You could also put in a 160* thermostat for summer

I became a fan of cool running engines when i got my diesel its cool running and subsequently gets 20,000km between oil change interval, which i actually stick to as bad as it sounds..