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water temp sensor
Posted: Tue Nov 10, 2015 5:06 pm
by narita
Ok so i have a 1/8 npt vdo sensor and a asi 1/8 nptf hose adapter.
Will the npt to nptf require sealant and if so which is the safest to use as to not alter the temp readings from the sensor?
Re: water temp sensor
Posted: Tue Nov 10, 2015 5:27 pm
by hks_kansei
Not sure if you need sealant, but frankly a little smear wont hurt.
No need to worry about the sealant being sensor safe with a water temp sensor, that only really applies to things like 02 sensors that can give weird readings with the fumes from the sealant.
Pretty much anything should work, as long as it can take the heat, and won't dissolve in water (i'm pretty sure all auto sealants are ok on both counts)
Re: water temp sensor
Posted: Tue Nov 10, 2015 7:17 pm
by madjak
Also thread tape works fairly well. I find it less messy than sealants.
Re: water temp sensor
Posted: Tue Nov 10, 2015 11:00 pm
by narita
May be worth noting the sensor grounds through the adapter. So using any sealant will need to be carefully.
Re: water temp sensor
Posted: Wed Nov 11, 2015 1:42 pm
by hks_kansei
narita wrote:May be worth noting the sensor grounds through the adapter. So using any sealant will need to be carefully.
ohhhh.....
In that case use nothing.
Re: water temp sensor
Posted: Wed Nov 11, 2015 2:56 pm
by bartmanftw
narita wrote:May be worth noting the sensor grounds through the adapter. So using any sealant will need to be carefully.
But doesn't the housing sit between two coolant hoses? I'd use sealant and add a ground from the sensor housing the engine to get a good ground.
Re: water temp sensor
Posted: Wed Nov 11, 2015 3:02 pm
by madjak
I've found with using sealant or thread tape that there must still be enough contact on the threads to earth it. I've always used some sort of sealant as I hate leaks and never had a problem with earthing.
Re: water temp sensor
Posted: Wed Nov 11, 2015 3:32 pm
by zossy1
madjak wrote:I've found with using sealant or thread tape that there must still be enough contact on the threads to earth it. I've always used some sort of sealant as I hate leaks and never had a problem with earthing.
+1
Re: water temp sensor
Posted: Wed Nov 11, 2015 6:54 pm
by sailaholic
You should use an electrically isolating but heat conducting sealant on all exposed faces of the sensor. Otherwise the sensor will ground through the coolant and promote engine destroying electrolysis. I find hysol to give good results.
http://www.loctite.com.au/3320_AUE_HTML ... 2643214337The high strength epoxy is strong enough to resist the erosion fretting that can effect the sensor due to the high water flows. Smearing a bit of the left over on the joins between radiator hosing and sensor adapter will also prevent crevice corrosion on the adapter.
I've almost missed your trolling Narita. I see your stilling working on your subtlety. It's getting pretty good, this one was almost a logic puzzle.
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Re: water temp sensor
Posted: Thu Nov 12, 2015 3:24 pm
by narita
Thanks.
Not trolling this time. The hose adapter has a seperate thread for the grounding wire. So the threads of the sensor need to be able to ground through the sensor.
Re: water temp sensor
Posted: Thu Nov 12, 2015 11:44 pm
by sailaholic
It the sensor truely needs to be grounded it can't be installed in a radiator hose with out providing a cable from the adapter to the body. Which isn't impossible just strongly recommended.
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Re: water temp sensor
Posted: Fri Nov 13, 2015 9:00 am
by hks_kansei
sailaholic wrote:It the sensor truely needs to be grounded it can't be installed in a radiator hose with out providing a cable from the adapter to the body. Which isn't impossible just strongly recommended.
narita wrote:The hose adapter has a seperate thread for the grounding wire.
Re: water temp sensor
Posted: Fri Nov 13, 2015 3:53 pm
by sailaholic
Hmm I read that differently. Not quite sure how now.
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