MazdaRx7Power

my car temp has been rising for the past 2 days, i'm thinking that the thermostat is getting stuck or the water seals are gone. so what i'm gonna do is hollow out the thermostat for now and see if it burns up water. but it still burns water after that then the seals are dying, which i will use a sealant process that was posted a while back to buy sometime for a rebuild kit..
i also bought new plugs cause the old ones are a little burnt right now.. if the thermostat was getting stuck would it burn water away like if it was overheating???