There is a potential for leaks to develope in fuel systems not specifically designed for ULSD. Chevron acknowledges this in a paper FTB-2-1, August, 2005. They also refer to a study by a California Governor's Task Force found at ftp://ftp.arb.ca.gov/carbis/reports/1639.pdf.

Chevron also recommends a maintanence schedule for nitrile rubber seals and the manufacturer's experience with lower aromatics diesel.

Jim W.