Guys as you know underneth the oem reservoir we have an outlet for the radiator and an outlet for our intercooler, I'm making my own coolant seperation kit, but I want to plug the intercooler hole, I'm just not sure what to plug it with, my coolant tank is full so I want to know what to use so save as much coolant as possible from leaking out, can I screw something in it? or does it have to be plugged if so how big does the plug need to be?

Thanks in advance guys!