Thanks for the response. I'm pretty sure that it's not a headgasket. Since the leak is appearing behind the pully, that leads me to the conclusion that it's the timing cover that's leaking.

Is this an easy DIYer job? Also, since the car has 140K miles, would it be good to adjust the timing chain when I had it all opened up?

Or...do I try and cheat and put some stop-leak in?