i changed everything due to the coolant system but still runs hot why?

What is your question?

I changed every part due to the coolant system my gages show its trying to overheat but it only goes two notches over the mandatory level half level line it did over heat and I got it fixed is it maybe a cheap thermostat or a blown head gasket code p0429 heat sensor I think I changed that too please need to know whts going on