OT: Overheating 89 Corolla, where is the water going?

[Microman]

This 89 Corolla, has had a rusty looking water, which I have drained and filled with 50% Antifreeze. But a few days later will be dirtly, so I did it again. Now it will get hot, and when I let it cool down, it will be very low on water. THe water is getting hot, and boiling off, and I cant figure out why.

I suppose the radiator could be clogged, or the thermostat could be stuck closed. I started it and let it get hot, after filling, and then took the radiator cap off to see if I could see any water flowing thru the Top Radiator hose. Could not see water flowing thru the hose, but steam started to come out the top of the radiator as it was getting hot, so I quit to research the issue.

Could take the radiator out, and have it flushed, or just take and replace the thermostat.

Thanks, for any ideas.