norty1 is spot on however, teflon tape is hard to use properly because you have to wrap it evenly and to just the right thickness for the "perfect seal". Too thin and you accomplished nothing, too thick and you could crack the fitting if its brittle from age. Most plumbers use pipe thread compound as it flows evenly and creates a perfect seal. I use Great White from Oatley. Just sayin!
2003 Designer Legacy 3590RLTS
2011 Bullet 215RBS - Sold
2010 F250SD PSD SRW CC SB
Timbrens, Rand McNally 7710RVND and
Pullrite SuperGlide 2700.