Posting this for a buddy with a 94 XJ with the 4.0

Well long story short he broke off the sending unit on the back of the head, while he drilled it out he nicked the top of the head and it slightly leaks coolant now.

Is it possible to use the newer style thermostat housing with the single sending unit for the computer and the gauge and just plug the sending unit on the head with a self tapping bolt?

Thanks

 

Did ya try teflon tape on sensor ?

 

he used an O ring and some "RIGHT STUFF" at the top of it and it sealed it, but he wants to have it sealed better to be sure if won't leak down the road.. Think Teflon tape would work better?

 

An easy option is to find a spot-facing tool and cut a shallow counterbore to make a machined fit for an o-ring (or better yet, an annealed copper gasket).

He could just be able to get away with Permatex "Liquid Metal" or a similar repair compound as a more or less permanent Band-aid.

 

Its a tapperd 1/8 pipe thread. Teflons best on them.

 

It seals with threads not surface contact.

 

Yes, you could relocate it and extend the wire.

But, why would a plug seal better than the sender? Same threads.

 

Use thread sealer. The sensors come new with it.

 

I suppose that's true.. You're always very wise about these sort of things.. Think just simple Teflon tape would work best?

 

I'm not a big fan of teflon tape - on anything other than residential water.

Once you've spent all night swimming in oil while you change valves and filters gummed up by degraded PTFE tape, you start having an unnatural hatred for it.

I'd use a good paste sealant and a proper repair of the head. The o-ring idea the OP spoke of is a good one with a little extra prep.