Radiator coolant boiling out of over flow tank and engine running hot because of it?

95 Toyota tercel. Yesterday out of no where I notcie a little bit of white smoke coming out from under my hood, I look down and see the temperature gauge is all the way above the H. Usually my temperature gauge sits in the middle. So I topped off the radiator fluid last night. This morning on my way to work, same... show more 95 Toyota tercel. Yesterday out of no where I notcie a little bit of white smoke coming out from under my hood, I look down and see the temperature gauge is all the way above the H. Usually my temperature gauge sits in the middle. So I topped off the radiator fluid last night. This morning on my way to work, same thing, white smoke coming out from under the hood and the gauge was all the way up. So I pulled over and checked and all the coolant was gone again. Tonight when I got home I put more coolant in while I had the car in park. I let the engine warm up a bit then, then I revved the engine a few times, as I revved the engine my friend said the overflow tank was overflowing. So then I got out and checked while he revved the engine, and coolant was coming out uncontrollably. The plastic lid seemed pretty tight, but I think it gets so hot and the pressure so high that it eventually blows off. Because when I checked it earlier it was off. Any way there was a bunch of coolant and steam coming out of the hose that goes from the radiatior cap to the coolant overflow tank. Why is my engine getting so hot? What can I do? What should I check first? I need my car for work. Please hellp. Thanks
Update: K Ang I plan on taking it to a shop, I don't want to mess anything up.

And Pete thanks. I was trying to find the leak when I seen it boiling over, and I figured that was where all the fluid was going. I will watch the video you posted. Thank you
Update 2: UPDATE!!! I think I found the culprit, but now I have another annoying problem! After reading posts on here and making sure the car was cool, I took the metal radiator cap off. I the washer and springer were off sitting inside the hole. Now the spring fell down the side of the hole and theres no way I can get to it... show more UPDATE!!! I think I found the culprit, but now I have another annoying problem! After reading posts on here and making sure the car was cool, I took the metal radiator cap off. I the washer and springer were off sitting inside the hole. Now the spring fell down the side of the hole and theres no way I can get to it without a magnet on a string or something like that. Hopefully it was just a bad radiator cap, I'll get a goo done in the morning before work, but now what to do about the spring? Can it get sucked into the water pump and break it?
Update 3: Bryan- I'm going to replace the radiator cap tomorrow, but now what about the spring from the old one? It fell down into my radiator. What trouble can it cause if I don't get it out. I don't feel like taking the radiator off and turning it upside down.
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