FWIW, I finally got tired of monkeying around with stock return lines that never seemed to last more than a year with bio, and splurged for the viton stuff. Ordered 10 feet from this site for $3.22/ft. http://www.mcmaster.com/asp/enter.asp?partnum=5119K111+
Casey Olympia, WA Biodiesel: "I drive in a persistent vegetative state" '87 300TD intercooler #22 (214k) '84 300D (212k) Gashuffer: '89 Vanagon Wolfsburg Edition (187K)
