Same thing happened to me.. I changed the fan clutch. It continued to heat up on idle. I had checked the coolant reservoir a thousand times.. It was filled to the line. After changing the clutch, it still heated up while idle. I then proceeded to open up the radiator cap (silver cap on the actual radiator, not the plastic cap on the reservoir) and I was surprised to find that the radiator was empty, I filled it up with 50/50 coolant made for MOPAR motors (You can find it at your local O'Reillys), and that fixed the issue. Before you replace the fan clutch, don't confy on the level of coolant in the plastic reservoir. Put coolant into the actual radiator, open up the silver cap near the radiator, you can actually hear if the radiator is empty (You will hear the liquid hitting the bottom (sounds like water into an empty jug). It could possibly be that there is a pipe clogged, or not a good transfer between the reservoir and the radiator..
