wcortesi

I apparently cured the situation. I took the drain tubes off in front and used some clear silicone to make sure the fittings don't leak and put some around the gasket on my OnStar antenna, although I couldn't see where either of them were leaking. No leaks for the last week and we've had our share of rain!

Well, apparently that's not the source of my leak. I'm baffled. I pulled down the headliner and although I can see signs of moisture, I can't identify where it's coming from. The drains all look good and work properly. I'm not sure what this tube does, but there's no hose up there to attach to it. https://goo.gl/photos/5H5g21aHYoincvKh7

This is the first post I've found that described the issue I'm having. Mine is and 08 that I bought new, but it only has 35K on it and I baby it. Suddenly my headliner is soaked just in the overhead console right in front of my sunroof. Naturally, I assumed it was the sunroof but the drains seem to be clear of junk and drain just fine when I tested it. Also, most people report the headliner gets wet by the A pillars when the drains are plugged, but mine is bone dry there. I looked at the back of my OnStar antenna and there is a split there. I crammed some dum-dum in there for the time being since it's pouring rain and dark outside right now, but we'll see if that cures the issue! (Of course I have a 24x28 shop, which is filled with my Avanti up on jack stands and my SL500 Convertible next to it, so the truck sits outside!)