'03 ES overheating at speed, but not idle

[Cobra]

friends car, '03 ES is overheating when driving at speed, and then it cools down when the car is stopped and idling. we've replaced the thermostat, but the problem still persists. we bled the system by pouring in coolant, and then running the engine with the heater on til hot, and according to the temp gauge, it still runs hot. temperature goes up to about 80% of the way, but never all the way to the red. both radiator fans are working, and there are no leaks as far as we can see. any ideas? thanks everyone

[Redhaze]

https://www.thegalantcenter.org/showthread.php?t=48585

a 2001? and a 2003? with the same problem ....

[Cobra]

https://www.thegalantcenter.org/showthread.php?t=48585

a 2001? and a 2003? with the same problem ....

the 2001 is mine. the 2003 is a friends. both are also white, which is quite the coincidence