Yes, that would be an easy and practical test, and I'll be doing that. Woody has me curious now what the pressure would build up to after plugging it; as that #dictates what boil protection we get w/ just distilled water. Thus, I'll be installing a low pressure gauge so I can test/monitor what the pressure does from startup to heatsoak. This will happen when the autox season starts up in a couple of months. Woody, thanks for sharing all the great testing your doing to improve our weak links in the IC system. Taking notes here.