Glad I started this thread. Maybe I am overthinking this whole thing. I don't even want to connect the heater hoses up. I was just planning on putting the nipples on and then capping the nipples. Would there be a easier way to just seal up the holes? I am worried that tapping the hole is going to be more complex then I originally planned. Looking at the hole you can see where part of the hole was already damaged. After listening to the guys on hear I am worried I am always going to have problems with it leaking.