weird cooling problem?

yesterday i was driving home and i noticed the temperature slowly rising by the time i had a chance to pull over it got up 2 about 230 deg. so i pulled over and shut the car off coolant was low but i didn't see a leak. went back and started the car once it built up pressure it dump what was left of the coolant out what looked to be under the water pump. so my first thought was it was the water pump gasket. had my friend bring some water jugs loosened the radiator cap so it wouldn't build up full pressure. we filled up the car and drove it home. temp never went passed 200 on the way home got home lost about a 1/2 gallon of water. so we turned off the car let it cool down and filled her back up and tighted the rad cap. we started the car and let it idle and 15 mins later still no leak and full of water? took her for about of 5-10 mins drive she stayed right under 190deg pulled back in the driveway no leaks and still full? later drove it for about 30 mins and same temp stayed at or a little under 190 no leaks and still full? anybody know whats going on here? thanks

Possible sticking thermostat.
If it stuck closed or partially closed you'll experience high temps.
Then when it opens properly all is back to normal.
It doesn't matter how old the thermostat is, I have had them bad out of the box.
You can get a replacement 180* stat at your local parts store and try replacing it and see if does it again.
While you have the stat out flush the cooling system in case there is some crap in there blocking the flow.

thats what i was thinking cause the top radiator hose got a pressurized but not like it should of been but why did it pour out the coolant from what looked to be under the water pump but doesn't now is what i cant understand?

I once had an old Chrysler that dumped water out of the water pump when it failed. But it came out much faster than you are describing. I'd change the t-stat and see how it goes.

You will need to put a pressure tester on it and pressurize to 14 - 16 psi.
Then you will be able to see the leak.
Do this before replacing the thermostat and flushing the system.
Need to find out where that leak is coming from.

ight i"ll do that and the first time when i pulled over and check for leak and didn't see anything so i started it and when it pressurized it did dump out the coolant like a water hose till it was pretty much totally empty.

and it only leaked that 1 time its seems fine now?

After giving it some more thought, a bad water pump will cause temps to rise as well as a sticking thermostat.
If you are sure it was leaking from the water pump then change it and the thermostat.
If your not 100% sure then have it pressure tested first to determine where it's leaking before throwing parts at it..

ight i"ll see if one of my friends have a pressure tester b4 bring it 2 a shop to test it. i"ll change the pump myself though hope there's a good wright up on it lol.