Best method for sealing threads that are in contact with oil???

[Dante04SRT]

I have a billet oil cap with the 1/8 NPT port on the top for my oil temp sending unit.

I keep having an issue with oil getting by the teflon that I'm using to seal the sending unit to the cap.

I've used a little tape, a lot of tape and every combination in between and I keep developing an oil leak at the threads of the sending unit!

Is standard teflon not meant for oil contact? If so, what is a better product? If oil was passing over it, it probably wouldn't be a problem but it's being forced against the sending unit (design of the cap) and therefore keeps springing a leak!

HELP!

[smokersteve]

any auto store will have thread locker for oil applications.

[npccpartsman]

I've never EVER had an issue with motor oil and teflon tape, and I've used a BUNCH of teflon tape in a lot higher pressure situations than this. Are you sure you don't have another problem like a crack in the cap or bad sending unit?? Over tightening pipe threads in aluminum can do that very quickly.

[rem1981]

Originally Posted by npccpartsman

I've never EVER had an issue with motor oil and teflon tape, and I've used a BUNCH of teflon tape in a lot higher pressure situations than this. Are you sure you don't have another problem like a crack in the cap or bad sending unit?? Over tightening pipe threads in aluminum can do that very quickly.

I can't say that I have ever had that issue with Teflon tape either. Hell, I didn't even know they made a tape specifically for oil applications. I'm wondering if there isn't another issue as well.

[APEowner]

Tape really should work but I've found that Permatex Teflon thread sealer is a bit more forgiving on less than perfect threads.

[esuitt]

Check for cracks. Teflon tape if over used/ tightened will cause cracks in fittings.
I always like using liquid teflon/ paste.

[Dante04SRT]

The cap and sender are brand new, no cracks/damage - This has leaked from out of the gate...

[rem1981]

Don't take this the wrong way, but are you sure you are using the right fitting? Sometimes the metric/standard equivalent of the right fitting is real close, but not close enough for a proper seal. Just throwing ideas out there.

[dazdillenger]

Use the liquid teflon, let it sit overnight. Problem solved!

[HAM_RADIO_MAN]

------- Loc-tite 545--------- Clean both threads with fast drying contact cleaner. Apply Loc-Tite 545 and assemble then let cure for 24 hrs. I have used this for hydraulic applications to 10000 psi works every time. Teflon tape should work unless your threads are damaged.

Thinking about this for a second. Doesn't an 05 have a factory oil temp sender? Be very very very sure that your new cap is the same in every way as the OEM cap. There have been a lot of crazy problems traced back to using a taller than OEM oil filter cap because it may not let the filter seal correctly. I have also heard of issues with the drain back valve hanging open.

We could use pics of the cap and sending unit. from your 1st post sounds like you might need an O-ring????