Overheating...., Diagnose my problem? Options

[95GTCelica]

Alright 6GC People I need your help...

Today after driving for about fifteen/twenty minutes I parked and noticed that the temp gauge read above the red line and the H. Popped the hood and heard gurgeling coming from the radiator with some overflow. I let it cool down for an hour then came back and drove around the block a couple times. I noticed that the temperature goes through the roof when it starts and slowly climbs. But when i hit about 40mph it cools down to about 3/4 of the way and when i stop it goes straight back up. I had a similar problem like this before and it was a bad water pump which was replaced a few weeks ago. Today there was no coolant on the ground just the few drops that spilled from the overflow. The engine seemed to be running fine and I wouldnt have noticed anything wrong with it unless i looked at the temp gauge. So can anyone help me? Any ideas? I'm stumped.

[95GTCelica]

eroded water pump, air pocket.

just to be sure its not the head gasket, get a combustion gas test kit. you add a chemical to a sample of your coolant and if it turns blue or something then you have CO2 in your coolant which means a combustion leak into the cooling system.

Well I'm going to try to take it to the mechanic tomorrow, should be the end of this probem. I really dont have too much time during the week to do this stuff. Although I learned a hell of alot with compression testing, changing the thermostat, and I actually want to do it myself so I can learn more. If I feel adventurous enough tomorrow I will give this combustion gas test thing a try. If not mechanic.

I still think it's your thermostat.

Really? Why do you say so? I just replaced it...Maybe I screwed it up somewhere?