Interesting....the schraeder valve is defective? That seems almost impossible. But here's a thought- maybe there is some dirt or something down in the valve preventing it from seating all the way closed? I don't think there's anything inherently wrong with slime in your tubes (but I do remember reading not too long ago that one mfg would not honor a warranty if they found sealant in a failed tube.

Anyway, I fly home tomorrow for the holidays, so will not be in Ohio for the next two weeks. There are plenty of trails around though, so if you are in the area, make an effort to ride the bike trails here. They're very nice.

Sounds like you have quite a Germanic adventure planned, and I hope you have a great time.