Check to make sure your fan comes on. If you have a temp meter it should come on at about 190-200 degrees F. Maybe change you coolant and use a 70% water 30% coolant mix with 8 capfulls of water wetter. If you don't have leaks you shouldn't have to change parts. Also check your T-stat which is less expensive to replace than a radiator. Start simple and work you way to a solution, not just a quick fix.