coolant leak at oil cooler

[Tony R]

I filled up the coolant system, in the motor I just rebuilt. I noticed I have coolant dripping from the oil cooler. It is coming out of the adapter that goes from the oil cooler to the flywheel housing. I understand what I have to do to remove it, but my question is, why is it leaking? I used a new gasket and I cleaned everything really well. Should I disassemble and use some sort of gasket sealer on it also? I'm just curious if anyone else has ran into this problem. Thanks Guys!