I was thumbing through the equivalent of Mainsheet for Porsche owners sitting in a waiting room today. In the tech area there was a question about repairing plastic gas tanks. I don't know if they are the same material as our plastic tanks, but the tech editor recommended Dow Corning RTV 730 to seal the leaks. Said he had successfully repaired several tank using it.
Anybody heard of this RTV 730?
Ken - here's the link to the dow product data info
http://www.dowcorning.com/applications/search/default.aspx?R=406EN