Chrysler Repair: 98 Cirrus runs rough and begins to overheat, outragous price, engine fan

Question
My vehicle overheats when idling at a light or in a drive-thru after i have been driving the car for 15min. The engine fan sounds like it is running but sometimes it has a rougher sound and during those times i will begin to overheat while sitting still.  Once i get moving again the temp returns to normal.  This only happens after i have been driving it and the egine is nice and warm.  What can i do to solve this problem before taking it to a shop and paying a outragous price for a problem i can't be sure about.  Thought about doing a radiator flush maybe the coolant isn't moving from build-up or is this a fan motor problem.  Like i said the fan seems to turn on and run fine except those times i am sitting still and even then i get normal sounds and no overheating...it seems to be at random times but its always while sitting still for long period of times.  I also seem to get oil leaking from around my oil filter even a few hours after having my oil changed if that might be a symptom of the bigger problem.  The leaking oil has never been enough to cause me to refill my oil before the next change.  If you have any suggestion how to begin solving this it would be great.  If i should need a flush telling me how to go about this myself would be a start.  Thanks

Answer
Hi Steve,
Because you didn't say you were loosing any coolant to speak of then at least we don't have to be concerned about any leaks in the cooling system. Because it only overheats when standing still (and when the fan may sound differently) I would suggest that you familiarize yourself with not only the normal fan sound, but also the appearance of the fan (how fast is it spinning) both when it sounds normal and when it doesn't, and when it doesn't can you tell if the speed is reduced or the blades are striking part of the shroud? It is normal for the fan to come on when the car is sitting still and the engine is warmed up, the issue is why isn't the fan doing its job when needed. Because you aren't overheating when you are moving I suspect the radiator and pump are o.k. so set aside the flush question for now. There is a low and a high speed radiator fan that operate independently depending upon how hot the engine is at the time. So the best thing to do is park somewhere and watch the whole cycle of the gauge rising and how the fans respond to the situation.
Then write me back and tell me what you observed. Also tell me which engine you have.
Roland