Need help with thermostat....

I had to change out the main radiator hose...the one that runs from the radiator to the thermostat housing....anyway the other one had a gash in it and after I changed it everything was fine....it has been about 1 week since the change and then today all of the sudden the temp went up almost to the red.....i pulled over and opened the hood and i could here the water boiling big time. I opened the reserve and that water was boiling also then it started spitting water out after i opened it. I went to autozone and the guys said that before i buy another thermostat....he said I have to purge it.

So i checked in the owners manual and it said to open the bleed valve...but i did not hear any air come out....any other ideas????....should i just buy a new thermostat...if so what brand and temp????

1997 GPGT.

Make sure your radiator cap is on tight. I had the same exact thing happen. Temp shot up and reserve tank boiling. While it was happening I got a rag and tried to turn the rad. cap and it wasnt quite tight enough. As soon as I got it tight the boiling immediately stopped. If the system cant pressurize it will overheat. Also make sure your cap and neck on the radiator area clean so it makes a good seal.

sometimes it takes hours to purge the air from ur system. make sure you turn the heat on full blast, to purge all the air from ur system.

Makes sure you turn the valve enough, you have to turn it almost until the screw comes out. If you see nothing coming out, assume air is escaping, keep running your engine until coolant starts trickling out.

Changing the thermostat might not be a bad idea if it is getting old, but if you havent had any trouble with it in the past, dont bother. If you still want to change it, get an AC Delco one, thats the official GM parts manufacturer. They only have 195 F ones. Test it in boiling water on your stovetop and use a meat thermometer to see what temperature it really opens (cant take credit for this trick, another forum member suggested it and it rocks !). Dont go for cheap thermostats, i put one of them in my car once, and my mechanic told me off quite harshly :(....thats when i was having overheating problems....

Another method to remove air is light squeezing of lower and upper rad. hose with cap off. Alternate sqeezing one side at a time, watch for bubbles gurgling up, and fluid level changes.