What thread sealer do you use?
 

Installing a in line fuel filter and not sure what kind of thread sealer to use on the fittings. What do you use? Thanks for the help.

there is an oil/gas resistant teflon tape that I have used. It is yellow. any hardward store would have it.

Most fuel filters are bevelled fittings with straight threads. If it is a pipe thread tapered fitting use teflon tape. If it is a compression or taper fitting the seal is made with the fitting shape not the threads and they should not be sealed.

Avoid Teflon tape, especially when using NPT fittings in aluminum housings for fear of cracks. Tape sucks anyway. For fuel use Permatex #1 on fittings and #2 on gaskets like the tank sender. (auto-parts store) For water use Rector seal #5 (hardware store)

Thanks, I used permatex thread sealer, and looks like my leak has stopped. Thanks for the info all!