when it's running good, it's just above the letter "N" on the temp gauge or a 1/4 of the way up. the temp guage has NORM along the side "N" being the lowest and "M" being the highest temp...
when it overheats it'll go all the way up to the "M" kinda looks like the fuel gauge when it's full... I turn off the car and water is spewing out of the reserve cap. The cap is on tight...
i am really starting to thing the radiator is blocked or gets blocked every so often or the thermostat gets stuck.
last night the temp went WAY high and a few moments later, it went back to normal like something released the water and circulated it...

i'm brainstorming and all i can thing of is the radiator and the thermostat?