Oil leak in temperature sensor

[phenomic]

I installed a temperature sensor and I believe it is leaking. I did it in an fbody which has a convenient place for installation. The vettes have a stock oil temp sensor on the ls1's so i tapped the removable piece. The sensor asked for 1/8 npt threads. My friend drilled and tapped it, he did an awesome job. I used some teflon tape to make a good seal and tightened the sensor all the way up.

For some reason, it is leaking, what can i do? Should I try removing the teflon tape and just going metal to metal, or possibly using loctite on those threads?

Here is a picture of what I am talking about:

 

[Drew99GT]

Instead of tape, I would use Permatex thread seal in a tube; it's like RTV consistency. If you put the tape on the wrong direction, it can unwind as you thread your piece in. After doing a bazillion sprinkler systems, I've found out the hard way many times about that phenomenon!

 

[1040 WreckerMan]

Also, with pipe threads you shouldn't be able to tighten the it "all the way." NPT are taper threads, so you should go about 1.5 turns or so and the fitting should start getting tight, then another 1.5 turns or so should be enough to seal it.

If the tape is used in the correct direction it can seal threads that are distorted better than the liquid sealant. Although that is an extreme case, I use mostly the liquid Teflon thread sealant, it works well.