Venture Chevrolet Motor Heating

Good morning, I need them to help me with a problem of my venture 97 engine 3.4. The ahuja of the temperature indicator reaches up to 3/4 and that is when the two radiator fans start. When I do a few laps and the temperature does not reach this point the fans do not start and start throwing the antifreeze as if it were boiling.
I change the temperature sensor, thermostat and the antifreeze (purging the system) and remains the same.
What do you recommend reviewing?
Greetings and thanks for addressing my topic.

Did you try the first speed of the electrventilator?, do you want to be damaged, now if it starts in three quarters it means that it is only activated in an emergency if you have a check -temperature bulb if you do not have it you can perform a parallel installation for the electrventilator so that it starts when it is neseousy and stop when it will let it do it Czech and warn your answer to indicate how the instruction is done and what materials you are going to use.

Hi Kikemec, I thank you for your recommendation, but let you tell you that I descend the location of this temperature bulb, or is it some physical thermometer that must be placed apart?

Water is boiling? Xq If it is not so it is common that the cover of the water storage that at the time has a pressurization valve this broken this makes the water do not circulate as it should and the water is scaled ... from now on greetings and let me know if there were solutions

The vulvo of Tenperature would be on the radiator, he usually has two or three cables, if he is not because I drop the engine you talk to me, one can install one on the path of the refrigeration system, only to approach you are sure to be sure that the problem passes through the fans and not by the motor nut, with cables.