I've had a 750 for 15 yrs. the only time it heat up is when the rad is plugged and it seems real easy to get it plugged especially between the oil cooler and rad itself. I pressure wasu the rad about every 100 hours. You should be able to see through it when clean even though it might look clean it won,t be unless you can see dayl;ight.I can tell when the rad is getting plugged because the hyd. oil temp starts to rise and it hardly ever does more than move a little bit when things are normal.