HI!

I have a C280 and it overheats when i drive it for a while.., it has no coolent leaks, coolent level is full, thermostate is new( and i also ran the car with out the thermostat and it still overheated), im thinking headgasket? or plugged RAD? or i hear something about a harness??? if anyone can help me out that would be great.,

thank you