Page 1 of 1

Fitting water temp sender - to PTFE or not?

Posted: Fri Sep 04, 2020 3:43 pm
by Pete Bags
Hi all,

I hope to spend this weekend fitting my new TIM electric water temp gauge and sender unit to my 1098 engine. I bought the gauge and sender unit as an 'all in one' kit from MiniSpares. The sender unit comes with a couple of adapters - as there is no washer, should I be using PTFE tape or similar to get a watertight seal - or would the PTFE interfere with the electrical grounding?

Many thanks in advance for your advice.

Pete

Re: Fitting water temp sender - to PTFE or not?

Posted: Fri Sep 04, 2020 3:46 pm
by Biggles1957
Pete I can't quite remember (it's been a few years since I did it!) but does the adaptor have a tapered thread so it seals without a washer?

Re: Fitting water temp sender - to PTFE or not?

Posted: Fri Sep 04, 2020 3:58 pm
by Pete Bags
A good question - I have yet to open the bag and have a look!

Re: Fitting water temp sender - to PTFE or not?

Posted: Fri Sep 04, 2020 4:27 pm
by newagetraveller
I would be inclined to use as small amount of ptfe tape, assume that when you tighten it up the sender will cut through it and make contact with the engine and then check that you have an electrical connection with a meter.

Re: Fitting water temp sender - to PTFE or not?

Posted: Fri Sep 04, 2020 4:44 pm
by philthehill
https://www.minispares.com/product/Clas ... o%20search

There is no requirement to use PTFE tape.
The transmitter and adapters (if required) should be self sealing.
Just make sure that the thread in the head is clean before fitting the transmitter/adapter(s).

https://www.minispares.com/product/Clas ... o%20search

Re: Fitting water temp sender - to PTFE or not?

Posted: Fri Sep 04, 2020 6:49 pm
by Pete Bags
Many thanks all, @Philthehill, the top link is the item I bought - I appreciate your comments and will report back how it goes.

All the best,
Pete

Re: Fitting water temp sender - to PTFE or not?

Posted: Sat Sep 05, 2020 10:48 am
by geoberni
Personally I'd use a little ptfe tape just at the top of the thread almost as a washer. Just because I could.
No need to overly worry about metal to metal contact for completing the circuit, the water will happily that :D

Re: Fitting water temp sender - to PTFE or not?

Posted: Sat Sep 05, 2020 12:10 pm
by philthehill
The electrical transmitter is sealed by the concave taper in the head and the convex taper at the inner end of the transmitter. The threads form no part of the sealing.

Re: Fitting water temp sender - to PTFE or not?

Posted: Sun Sep 06, 2020 11:07 am
by Bowie69
geoberni wrote:
Sat Sep 05, 2020 10:48 am
Personally I'd use a little ptfe tape just at the top of the thread almost as a washer. Just because I could.
No need to overly worry about metal to metal contact for completing the circuit, the water will happily that :D
Incorrect, the circuit needs to be via the block directly, the water will form a very poor electrical connection, even with coolant in it.

Re: Fitting water temp sender - to PTFE or not?

Posted: Sun Sep 06, 2020 4:52 pm
by geoberni
Bowie69 wrote:
Sun Sep 06, 2020 11:07 am


Incorrect, the circuit needs to be via the block directly, the water will form a very poor electrical connection, even with coolant in it.
I bow to your experience. I've personally always found water a very good and often most inconvenient conductor.
Though I admit I've never relied on it for the temp sender. :wink: