rad or clutch fan?

runs good at night, and cool cloudy days, runs hot in hot days, and overheats in idling stop n go traffic, if I can get upt to 60km for 1/2 mile it will cool to 3/4, hiway in really hot days holds at 3/4 temp guage, rad has been been backwashed and looks clean, -budget for only one, fan or rad?

Same thing happend to my 91, when up to temp, CAREFULLY check section of radiator right in front of fan clutch for uniform heat, my rad had a clogged section in front of the clutch which kept it from engaging even though I was overheating. Also a worn pump can contribute to the problem. I realize the question is quite old but hopefully the info will help someone.