My car is getting hot, I replaced thermostat.

Could be a broken plastic water pump impeller.

Make sure you have good return flow of coolant into the reservoir when the engine is running.

If you have no flow, then that's a sign that the water pump is not pumping.

The impellers can fail intermittently, but eventually freewheel or break apart completely.

Thomas

Also pressure check for internal leaks and check radiator for cold spots. If they have cold spots it's not any good.