coolant and thermostat question, re-updated with a twist Options

[HaysoosKreesto]

Hey everyone, it's been a long time since my last post. Car still runs beautifully but my first ever problem arose that perhaps a friendly user might help me solve, or know of the page that solves it.

So my coolant has been boiling out of the reservoir after driving on the freeway and coming to a stop. I tried changing the thermostat, maybe the thermostat is defective? Well assuming it's not (I do plan on going back to the dealership and asking for a new one in exchange however) perhaps it may be something else. Does anyone know where the sensor to monitor the temperature of the coolant before the radiator fan kicks in is?

I'm having trouble searching for it, but I figured that if I change the sensor and the thermostat (again) then maybe my problems would be solved.

Also if anyone has any idea as to why it continues to do this, with all appreciation I urge you to please respond.

Thank you and much love,
Rafael.

Edit: check last picture to see the new situation

This post has been edited by HaysoosKreesto: Aug 16, 2013 - 10:16 AM

[Galcobar]

All of the sensors and fan switches can be tested with a multimeter and a pot of water. Functionally, only the engine coolant temperature sensor and the temperature fan switch matter, but my first question is whether you've checked the radiator cap.

If the cap is faulty it will not maintain the pressure in the coolant system which keeps the coolant from boiling at operating temperatures, and will allow the coolant to spill into the reservoir.