Most common mystery leak at that location on this 3.8 engine is the plastic 90° heater hose connector in front of intake manifold, NOT the manifold,, "that get the blame",, but the connector has cracked. Suggest using improved metal type NAPA part # 6601942. Best to have a mechanic do a pressure test and then the parts replacement! It's called a hose connector but it actually connects the manifold to the belt tensioner assembly which coolant passes through! Sounds crazy don't it!!... Just get a mechanic to replace it. There is another one that comes with that part #, it too goes into the tensioner, 'good ' mechanic will know what to do!!