I have a 1990 4runnet with the V6 in it. I can drive it all day and have no issues. I can drive on the local interstate all day no problems. But I get anywhere where I run 70 or above for long distances then I have problems. Seems like if I keep the rpms under 3000 I have no issues but if it goes above that it will run hot. I can slow down and it will cool off pretty quickly. Well usually. I am posting this while broke down on the side of the road. It was doing great at doing 70 then it overheated again. This time it got so hot it shut off. I don't understand why 3000 is the magic number?