Water Temp Sending Unit Installation

[bartman]

I purchased a Water Temperature Sending Unit along with a new retaining nut from MSA (http://www.thezstore.com/page/TZS/PROD/SCC13/16-7110 & http://www.thezstore.com/page/TZS/PROD/SCC13/16-7115). My question is how do you install this so that it doesn't leak.

The retaining nut fits around the sending unit, but it doesn't seem to be tight enough to prevent water from leaking between the two. I bought a sending unit from a local parts store a few days earlier, and that one leaks when I installed it with the old retaining nut. I figure I'd get a new one and a nut to see if it would solve the problem, but it doesn't look like it will.

[ChrisA]

Hey bartman,

Are you installing the stock sending unit on the V8?

I installed a new one from Courtesy Nissan and with a little thread sealant at the hex end of the nut. Mine sealed just fine. Too much sealant and you might lose the ground connection. No sealant and its sure to leak. At least at my house anyway!

[bartman]

:stupid:

Hey bartman,

Are you installing the stock sending unit on the V8?

I installed a new one from Courtesy Nissan and with a little thread sealant at the hex end of the nut. Mine sealed just fine. Too much sealant and you might lose the ground connection. No sealant and its sure to leak. At least at my house anyway!

Yes, I installed both the stock water temperature sending unit and the stock oil pressure sending units on my V8 (using stock gauges for them).

I think that it's leaking between the nut and the sending unit, not the nut and the block...but I could be wrong. Good point about the thread sealant though, I didn't think about losing the ground connection. I used thread tape on the last one I installed and the gauge stopped working...you may have solved that problem.

It seems to me that the retaining nut should have a better seal on the sending unit itself to keep it from moving around and leaking.

[zhead240]

is anti-seize grease the same as sealant?

[ChrisA]

Hi bartman,

Umm, the thread size and pitch on the "Nissan" sending unit is more than likely metric. The hole in your V8 is likely to be standard "americanized" pipe thread. That could potentially cause the leak. Unless the threads are exactly the same or darn close.

Hi zhead240,

The answer to your question is "no".

I use both in my garage. And they are completely different compounds.

The anti-seize is a blend of aluminum, copper and graphite lubricants in a petroleum base made to do what it says. Keep materials from bonding, rusting, seizing to each other.

The thread sealant is a polymeric paste/lubricant with teflon and polyvinyl resins. Oh yeah, Castor Oil!!

Use the anti-seize on bolt assemblies, use the thread sealer on connections that carry water/oil/air, sometimes gas, but gas will eat it under direct contact.

FWIW,

Chris A.

[bartman]

Hi bartman,

Umm, the thread size and pitch on the "Nissan" sending unit is more than likely metric. The hole in your V8 is likely to be standard "americanized" pipe thread. That could potentially cause the leak. Unless the threads are exactly the same or darn close...

I think the threads are both the same NPT.

[ChrisA]

I think the threads are both the same NPT.

Hmmmm.....well, if I recall correctly, the nut I got from Courtesy Nissan had a pretty defined edge opposite the hex that really pushed down on the sending unit. And the sending unit had a raised ridge in the middle or so of the its body. I remember thinking it was a pretty simple bit of engineering.

Do you think if you tightened it down a little more that might help?

I'm running out of suggestions. The nut wasnt out of round at all do you remember? Its a pretty thin cross section.

Keep at it, you'll get it.

Chris A.

[bartman]

Hmmmm.....well, if I recall correctly, the nut I got from Courtesy Nissan had a pretty defined edge opposite the hex that really pushed down on the sending unit. And the sending unit had a raised ridge in the middle or so of the its body. I remember thinking it was a pretty simple bit of engineering.

Do you think if you tightened it down a little more that might help?

I'm running out of suggestions. The nut wasnt out of round at all do you remember? Its a pretty thin cross section.

Keep at it, you'll get it.

Chris A.

I did some more checking, and it appears you are correct! I need an adapter to make it fit correctly, and they have them at JTR (http://www.jagsthatrun.com/Pages/Parts_DATZ_Wat-Temp-Send.html). I ordered one today and I'll give that a try.

Thanks for your help.

[ChrisA]

You're welcome, hope it works and glad I could help sort-of.

Chris A.