I got this 1990 toyota pickup 3.0l v6 5 speed manual. After repairing some stuff here and there i got some temp plates. The truck overheated so i checked the thermistat as reccomended online. Thermistat was fine in the pot of boiling water. Rad cap for overflow spring was fine not to much resistantce. Rad fan seemed fine so water pump and clutchpack is fine. Flushed the rad and ran cleaner and water through the system yet still overheating the only thing i can think of is the block is clogged. Help is truely appriciated. Also just a final note heat is minimal if that matters in the cab. Oh and also it only overheats above 40 kilometers per hr