My jeep's been overheating lately. It keeps doing it in stop and go traffic. So, a friend of mine who's dad is a mechanic suggested replacing the fan clutch, which really did need replacing, so I did. It seemed to be going good for about a day. It overheated on me again the other day. Could anybody suggest to me some good ideas that could resolve the problem, or help check what the problem is? I know jack about vehicles.