What would cause my engine to overheat when idling.

Thank you. Please forgive my lack of knowledge: If I simply replace the radiator fan should that solve the problem? I'm assuming this is a immediate fix or risking a blown engine?

The fans and their circuits will have to be tested to find out why they're not working.... Good repair shop with proper testing equipment (scan tool etc) can do this. A diy'er can test the fuses and possibly relay but that's about it!... Really need hands-on help... Try turning on A/C to see if fans start running. Post results.