Should there be an O-ring or crush washer on the oil pressure sender elbow?

[rang-a-stang]

I'm about to put the oil pressure sensor and elbow back on my 401. The elbow is all clean and painted. Just about to install when I realized I am not sure how to seal it... Does it just get a little RTV on the threads going into the block? Should there be an O-ring on there? A crush washer? For clarity, I am only speaking on the elbow that threads into the block, not the actual sender.... actually, Same question for the sender...

[babywag]

I?ve never used anything on them just snugged them down.
They?re NPT so unless threads damaged should seal.
If you?re worried about leak(s) use some teflon paste/tape.

[joe]

As Tony said, it's pipe thread so it's the threads that do the sealing.

[johnsonic]

If you do use tape, don't put it on too thick as the sender grounds to the block & you'll need a thread or two to break through the tape.

[rang-a-stang]

copy all, Thank you Gentlemen. I put it in, dry. Hopefully (probably) it seals.

[Ristow]

WHY DID NOBODY TELL HIM IT TAKES A LEFT HANDED METRIC ORING???

[rang-a-stang]

WHY DID NOBODY TELL HIM IT TAKES A LEFT HANDED METRIC ORING???

BWWAHAHAHAHA!!!!!
I used a little prop wash to clean it, lubed it up with some relative bearing grease, and gently torqued it in with a left handed crescent wrench. I am hoping those will help prevent it from leaking...

[Heavy_Metal_Thunder_81]

I put it in dry.

Am I the only one who giggled at this or has the military corrupted my mind?