2001 saturn sl2 overheat

saturn
sl
airconditioning

#1

my saturn sl2 is in pretty good shape, but the only major problem is the overheating. it overheats when idling or driving locally, but is mostly alright on the highway. i thought i had the problem licked when i was told i had a crack in my radiator, so they replaced it; the problem, however, returned. the only solution to this problem that i have found works is to keep the A/C or the front window defroster on. this leads to me leaving the defrost on low and middle-temp about 90% of the time, and A/C in the summer the other 10%.



any clue what could be causing my problem?

thanks!