changed radiator and thermostat in sunfire but still overheating

I have bought new thermostats that did not work. Sometimes you have to put in two or three thermostats to get a good one. Also, you might need to power flush your engine block and radiator. I think this about $80 and will restore and open up all the cooling passages.

Drill out the rivet that's supposed to increase startup time...un-necessary and good for only in cold climates for heatin' it up but quick~ The rivet is nonsense...gets clipped easily with a dikes~

get a 15 dollar thermo-spot gun to find out where the hot spots are ~

there may be a bleeder on the return hose for the heater core (the highest spot) would be an after-engineered item as if there was a problem with air not being carried with coolant stream a mechanic may have put one there ...at the exit hose of the heater core~ don't think these are factory~

https://www.google.com/#q=1998+Pontiac+Sunfire+radiator&tbm=shop