More than likely its the 'O' ring in the thermostat housing.Remove the Alternator to gain access.
John J., November 2009
it is the thermastat housing
bob, September 2008
Hi Fran, in that area you have the water pump and the thermostat housing, to try to narrow it down remove the alternator and see if you can see any area's of staining where the antifreeze has leaked