How to recognise an original water temp; transmitter.

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MIG Wielder
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How to recognise an original water temp; transmitter.

#1 Post by MIG Wielder »

There are a lot of after market water temp; transmitters about.
This is what an original one should look like.
When cleaned off the body should be in copper, not brass and etched on the casing are the words
" Smiths Industries LTD. Made in U.K. " .
The resistance should be about 900 ohms at room temperature.
Tony.

Edit July 2018 : These temperature senders have a problem after use for some years. The earthing for the gauge / sender is from the copper sensor casing to the mild steel of the threaded section. Over time this connection deteriorates and the gauge reading drops from normal. The solution is to use silver loaded epoxy on the join between the copper and the steel after cleaning it up. In my case the earthing resistance was around 300 ohms. Cleaning and adding the silver epoxy reduced this to <1 ohm.

And some measurements.
1. A set of data points relating water temp; gauge reading to the simulated temperature sender resistance with constant 13.5V in to the mechanical voltage stabiliser ( nominal 10V output) with a simulated load of 150 ohms for the fuel gauge.

First indication : 180 ohms.
"1/4" on the gauge : 100 ohms.
"1/2" = N on the gauge : 68 ohms.
"3/4 on the gauge : 47 ohms.
Full scale : 22 ohms.

So, very non-linear
Attachments
orig temp tx.JPG
orig temp tx.JPG (64.35 KiB) Viewed 2749 times
Last edited by MIG Wielder on Tue Jul 10, 2018 6:07 pm, edited 1 time in total.
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Mad Mart
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Re: How to recognise an original water temp; transmitter.

#2 Post by Mad Mart »

Thanks Tony.
Sprintless for the first time in 35+ years. :boggle2: ... Still Sprintless.

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Re: How to recognise an original water temp; transmitter.

#3 Post by Dolly-Dimple »

Excellent! Many thanks.

Kind Regards

Russell
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Re: How to recognise an original water temp; transmitter.

#4 Post by Toledo Man »

How do we get hold of one? The only ones that seem to be available are the generic ones which were made for the Series Land Rovers.
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Re: How to recognise an original water temp; transmitter.

#5 Post by GTS290N »

NOS? dunno.

Buy replacements from Robsport, as posted elsewhere on the forum.
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Re: How to recognise an original water temp; transmitter.

#6 Post by Toledo Man »

LD Parts (Stag specialist) do a temperature sender which might be suitable. They reckon it should work as intended.
Toledo Man

West Yorkshire Area Organiser
Meetings take place on the first Wednesday of the month at 8.00pm at The Railway, 1 Birstall Lane, Drighlington, Bradford, BD11 1JJ

2003 Volvo XC90 D5 SE (PX53 OVZ - The daily driver)
2009 Mercedes-Benz W204 C200 CDI Sport (BJ58 NCV - The 2nd car)
1991 Toyota Celica GT (J481 ONB - a project car)
Former stable of SAY 414M (1974 Toledo), GRH 244D (1966 1300fwd), CDB 324L (1973 1500fwd), GGN 573J (1971 1500fwd), DCP 625S (1977 Dolomite 1300) & LCG 367N (1975 Dolomite Sprint), NYE 751L (1972 Dolomite 1850 auto) plus 5 Acclaims and that's just the Triumphs!

Check my blog at http://triumphtoledo.blogspot.com
My YouTube Channel with a bit of Dolomite content.

"There is only one way to avoid criticsm: Do nothing, say nothing and BE nothing." Aristotle
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