When towing a 12,000lbs fith wheel my obs likes to run hot when climing long grades when the amp temp is over 75deg. 230-235 is when I'm getting out of it, my egts never get over 1250. I dont no if the Hyper max taper core is blocking to much air or if the stage 3 injectors are to big. The trans temp runs 15 deg below the trucks temp. I've had the radator cleaned and rodded. Has any body found a extra heavy duty radator. I've found by placing a close ball valve in heater hose it slows the rate of temp clime. Also Water wetter has slowed the rate but not fixed it.