x2 on the stuck thermo.....even tho it was replaced, i would still check it again

 

a bad thermost will usually give you a knocking sound when you turn off the motor and the water starts to boil. it is soon followed by it puking the water out.

spray some water on the radiator after you stop a hot engine. see if the water eveaporates evenly or if there are spots that stay wet. it might indicate a section of the core that is plugged.

if there is a fan clutch is it operating properly?
is the shroud missing?
have you checked the timing?

you can also have a buildup of rust in the cooling passages in the engine.

when the thermostat opens do you see a good flow of water.

a thermostat that is stuck open can flow the water too fast to let it cool.

is it really overheating or is the guage just reading high?

 

low coolant would make it overheat.

an air pocket would bee unusual in that car. if it has air conditioning, cycle the heat lever after it warms up.

if you're loosing coolant, have it pressure tested.