1999 honda cr-v over heating while driveing. normal rpms for 75 to 80 on highway on 1999 Honda CR-V

I replaced the thermostat thinking it was froze open no help. it takes driveing the car all day in town or about 35 to 40 miles on the highway. if i keep the rpms at about 2500 when im at a stop it stays cool.

Asked by for the 1999 Honda CR-V