Rodolfo,<P>Gord and I rarely differ on things, but I'll disagree with putting in a thermostat that has a different temperature rating than called for by the factory.<P>I'm going to assume you're familiar with what this truck should and should not do, so I'll assume something is wrong with your cooling system. (This means I assume the engine is in good running order, not having fuel delivery problems). I suspect your radiator may be partially blocked either on the inside or the outside. Have the radiator removed and professionally cleaned on the inside. If it's partly blocked on the inside, an auto parts store flush will not clean it. Here in the US what you need would be to have the radiator "rodded" which literally means the use of thin rods to open up clogged passages.<P>While the radiator is out, you should put a new thermostat in if its age is unknown.<P>Also, be sure your transmission fluid is fresh as the transmission probably has an oil cooler that can heat up the radiator.<P>DougM