Why is antifreeze leaking out the top of the container?

I have a 2000 Ford Taurus. When I don't drive it or anything nothing happens, but sometimes when i get done driving it it overflows out the top of the antifreeze container. It doesn't do this all of the time, but it happens every once in awhile. I didn't over-fill it either, so that isn't the... show more I have a 2000 Ford Taurus. When I don't drive it or anything nothing happens, but sometimes when i get done driving it it overflows out the top of the antifreeze container. It doesn't do this all of the time, but it happens every once in awhile. I didn't over-fill it either, so that isn't the problem. Could someone please help me out and tell me what's wrong? And how much would it cost to fix?
4 answers 4