Well took the trailer out to my buddy who works at discount tire. needed to put tires on it before our trip next week and get the tires rotated and balanced on the limo. did all stop and go on the way out there (15 miles to the shop from my house) as i took side streets the whole way cause the tires on the trailer were junk (didnt trust them on the highway). drove pretty easy the whole time and wasnt doin race car starts or anything, jsut easy driving. Outside temp was 106*, a/c on, running tow/haul. oil temps peaked at 220* due to the fan shutting off once on the way out but it soon kicked right back on and never kicked back off. With the fan on, temps wouldnt move above 210. Mind you, this is all stop and go in traffic lights going no faster than 50mph and you could watch the temp drop as i idled at stop lights.
on the way back i played a little harder and hit the highway. onto the on ramp i was about 3/4+ throttle trying to pick a place in line since everyone wanted to be dicks and not let me in (i still won lol). temps hit 215* after. Did another almost WOT run to get around a trucker and see how she pulled from 50 to 75mph. temps jumped to 230* and stayed, pressure was at 50psi at 1800 rpm (stock gauge). got back out of it and slowed and did another pull up a little overpass at WOT from 50 to 80 this time. temps stayed at 230* and pressure stayed the same. jumped straight off to my turn off and sat at the light for at most 1 min. temps were already falling. they were about 220* by the time i turned and got back into it again, pressure climed some to about 55psi. ran it hard from 10mph to 60mph and got out of it due to traffic coming. temp was back at 230 and stayed by about 50mph, pressure still at 50psi. A/c on, Fan on the whole time, 106* outside temp, and all on the same big tow tune. ECT was constant at 200* the whole drive. Now, the coolant temp gauge on my truck is slow reacting as well. When i had my edge on the truck looooong ago, i could monitor ECT and watch it hit 225* by the time the gauge needle would finally creep to 205/210* pulling a long hill loaded. So i personally dont trust the ECT gauge in our trucks as "extremely accurate" ways to measure what we are doing but it does a decent job for 99% of what i do.
Now i have no doubt ill see higher than 230 pullin a hill loaded but i was surprised i didnt see higher for as hard as i was pushing it. trailer is around 7200lbs. makes me feel a bit more comfortable goin next weekend. This is also on a fresh oil change to Rotella T6 syn oil.