Oil leak at base of distributor..

Hello, I just re-installed my intake manifold with a new gasket and now there is an oil leak behind the intake manifold on the base of the distributor. I used the red RTV on the bottom of the cork gasket. Does this mean I have to drain the coolant and get new gasket again? What is the best way to prevent the leak. This was my first time changing the manifold and valve gasket. No leak on the valve gasket.
Thanks
Bach