iauch

i bought a 93 loyale a few weeks ago and it ran great around town. I took it out on the highway and it would overheat. It would only run hot when driving at high rpms. I replaced the thermostat and still has problem. I took it to a shop who found no problems with the coolant system and suggested that the tranny was not shifting into overdrive as when riding a 55mph it was running around 3250 rpms. After this, i drained the old trans. fluid and filled it with new fluid. After this the water pump began to leak fluid from the weep hole. I took it to a shop and had the waterpump replaced as well as the timing belts. It is now overheating when idling and after only 3 minutes of driving! I noticed when it was hot the upper radiator hose was hot but not full and there was a gurgling sound coming from the thermostat reservoir. I took out the thermostat and have to wait until tomorrow to get a new gasket from auto zone. I was going to try running it without the thermostat to see if it was maybe stuck closed. Am not sure where to turn next. the fan is coming on, there is no coolant leak, is it possible the brand new thermostat or water pump failed?