You can only look for pressure leaks when the coolant is HOT and the engine turned off. First clean the plastic tank, remove the cap and clean that also. Then run the engine and get the coolant hot enough to turn the engine fan on (AC off). Get a clean white paper towel and go over the tank, the small coolant hose, the passenger side of the radiator (that's where the radiator breaks first).

Last time I looked, the drain is under the radiator, passenger side. It is black plastic. The air guide must be removed.

The hard top C70's are nice! Waiting for the pic of Draco.
--
Keeping it running is better than buying new