If it's on the passenger side then it's probably the aux water pump. Mine went out and started leaking bad. At first it was small leaks, in the end was adding water and coolant evertime I drove. The part, which could not be located at any local parts store, is availible through our host for around $100. It took me 5 mins to put it on. I'd look for the cause of the leak first before making assumptions about what might be causing it. Good luck.