I agree with the other posts. I tend to believe it is transmission fluid leakage. The fan can cause it to spread around the engine compartment usually behind where the leakage is occurring. The easiest way to locate it, is to first watch for low fluid levels, both in the transmission and the power steering unit. Next, go to the car wash and wash all the oil you can off the engine and watch closely for the next couple days to see where the oil is coming from. With a little luck and a small mirror, you should be able to catch sight of where the leak originates before it creates a new mess.