Civic Ex overheating 140K

Well my civic only overheats after very long trips say 200 miles and not so much overheat but get hot it goes over the middle. It has a new radiator thermostat, fluid flush. The one thing I forgot is to bleed the system. I mean it does not start overheating till after it stops for a while so I think there may be an air pocket. Do you think it's because I did not bleed the system? The engine is in perfect condition it's quite, same power as always never had a single problem, I just swaped the radiator because the old one had a crack near the hose (it was plastic). My engine sounds better then new civics. I'm really anal about maintenance. Everything inside and out is clean as a whistle. Give me some input am I forgetting anything?

Def make sure to bleed the system of any air (make sure the temperature control knob is on max heat while doing this).

So it's fine until you stop? It could be your coolant temperature switch that tells the radiator fan to turn on or it could be the fan relay is getting lazy. GL