So to be clear - I leave it open? I don't have a pcv setup - just have draft tube cleaned up and installed. I'm not arguing, I just thought it was funny a 70 yr old guy in my town was around and it drove him nuts! He was a mechanic at a Chevy dealer for 30 years and is just baffled he can't ever remember that hole. His suggestion was to jb weld it and paint over it. Glad I asked. I'll definitely leave it open if that's what it's for.