VE>When using Teflon tape in automotive service, always leave the first two
VE>threads of the fitting bare and never use Teflon tape when installing
VE>electircal switches that ground through the threads -- use Permatex. 

Loctite makes an excellent Teflon based thick fluid pipe seal now days,
gooey white stuff, neat smell.  Available as Loctite PST commercially
and I think 565 or 569 in larger tubes for bigger users.  Really good
crap IMHO, have used it to seal 3000+ psi servo-hydraulic test equipment
lines using AN pipe threads sort of incorrectly as I needed to in order
to get the proper adapter in a pinch.  This stuff does not harden up
quite as much as classic Permatex, and you can dissasemble later easily
if need me, would be excellent on electrical oil pressure senders I
figure
but have not had opportunity to try.

John