Coolant Problem :(
 

So, today i was leaving the beach and was nearly half-way home and my low coolant light started buzzing, i pulled over immediately and my AST was literally bubbling, at the plastic split, fluid was coming out. So, i put about a gallon of water in it just so i could make it home and figure it out. By, the time i made it home about 10 mins worth of driving, the low coolant was coming on again, i lifted the hood to hear the same bubbling and boiling noises, along with the AST bubbling out fluid. Anyways, i flushed the system and refilled it with coolant, but am still having the same problem. I'm not sure whats making the car heat up so fast to the point of boiling the fluid in there, could it be a dreaded broken water seal? Bad AST? Any help would be appreciated, thanks in advance

Wait, you didnt replace the ast? Replace or delete it asap and see if that fixes the problem. Start with the simple/cheap stuff first before jumping to the conclusion it is a water seal failure

What temps are you seeing. Do you have a power fc or an aftermarket water gauge? If its getting to hot it could also be the t-stat or radiator cap. Easy cheap parts is the best way to go before jumping to a motor

No, my car is pretty much stock, i honestly just wanted to get a good feel for a Rx-7 and see if i wanted to buy one back in the states. I don't have any white smoke on start up, after i fill it up i can drive it and it runs fine for a little while, once i park the coolant starts dropping out. Though the temps never goes above a 1/3 on the gauge (it climbed almost to 2/3's on the way home from the beach before i could stop and fill her up) I just ordered a petit AST, so hopefully that fixes my problem, i plan on looking for any cracked or dislodged hoses tomorrow just to be sure. Any other advice would be helpful

Would confusing the leads to the overflow tanks and the thermostat housing from the AST cause coolant to "disappear"?