Was on 404 north bound yesterday rush hour heavy traffic.Noticed my temp creeping up 202f ,204,208......224. Thats in bumper to bumper.So got on 407 headed east the temp went down to normal operating temp at speed. Not losing any antifreeze, just installed a new oem thermostat 195 degree. When tuned had fan low speed setting set to 186 degrees. Any ideas on what could be causing this issue. And how hot is too hot . Thanks