engine running hot changed thermostat still running hot
Does it overheat all the time? Or just in traffic?
If just hot in traffic - Is your electric fan running when hot? Make sure it is.
If is hot all the time, could be a clogged radiator.
Could be a head gasket. Do you see oily stuff floating in the coolant? Take off the radiator car when cold and fire it up. do you see bubbles in the plastic tank? Both are secondary symptoms of a blown head gasket. Time to run a compression test.