Temperature gauge sender

[KugaWestie]

Now the car is mot’d and taxed after it’s 9 year sabbatical, I have noticed my temperature gauge is not working.

Taking the sender wire off and earthing it sends the gauge immediately off the scale hot, so proves the gauge is working.

I fitted the Caterham sender in the Range Rover sender location and went for a test run tonight, and the gauge is still not working.

The below video link shows a quick test earthing the Caterham sender with the sender wire still connected. You can hear the fans running in the background and the engine is hot. So the gauge shoots to hot and then when I remove the temp earth it drops to cold.

Black bezel white faced gauges.

https://youtu.be/n5yiAHBg2Q4

Any ideas gents?

Edited by KugaWestie on Friday 12th August 19:48

[bobfather]

The sender may not have continuity with the head. Did you use thread-tape, if so you need to remove it. Easy to test, just temporarily earth the sender body to the block

[KugaWestie]

bobfather said:

The sender may not have continuity with the head. Did you use thread-tape, if so you need to remove it

No thread tape or sealant used

[bobfather]

KugaWestie said:

No thread tape or sealant used

Run a temporary wire from the sender directly to the gauge. This will eliminate (or prove) a wiring issue

[KugaWestie]

bobfather said:

Run a temporary wire from the sender directly to the gauge. This will eliminate (or prove) a wiring issue

I have already proven the wire. It has been continuity tested using a multimeter and the fact that the gauge goes to hot when I earth the cable at the sender end also proves the wire is good surely

[Belle427]

Strange but can only be a faulty or mismatched sender surely?
Was the sender recommended here?

[Polly Grigora]

It wouldn't be the first time that a faulty gauge has worked with max voltage applied to it

[trumpet1608]

I could well be wrong but I thought that the Caterham sender was to fix temp gauge misreading on Caerbont gauges with aluminium bezels.

Aren't the black bezel gauges made by ETB?

All the best

Dick

[KugaWestie]

trumpet1608 said:

I could well be wrong but I thought that the Caterham sender was to fix temp gauge misreading on Caerbont gauges with aluminium bezels.

Aren't the black bezel gauges made by ETB?

All the best

Dick

That’s what I am trying to establish

[Polly Grigora]

Place original sender in a tub of hot water

Get hold of a multimeter

Does resistance of sender reduce as sender warms up

You can do the same test with any other sender but check the original first

[Englishman]

trumpet1608 said:

I could well be wrong but I thought that the Caterham sender was to fix temp gauge misreading on Caerbont gauges with aluminium bezels.

Aren't the black bezel gauges made by ETB?

All the best

Dick

Quite right. Mabe this one is correct?

https://www.etbinstruments.com/index.php?route=pro...

[KugaWestie]

Englishman said:

trumpet1608 said:

I could well be wrong but I thought that the Caterham sender was to fix temp gauge misreading on Caerbont gauges with aluminium bezels.

Aren't the black bezel gauges made by ETB?

All the best

Dick

Quite right. Mabe this one is correct?

https://www.etbinstruments.com/index.php?route=pro...

Thanks David, I have emailed ETB to ask if the one you linked is compatible

Edited by KugaWestie on Sunday 14th August 07:51

[andrewbr]

Very interested in this, please report back.

Also per the thread in the Griffith forum, is there an alternate location for the temp sender for our early cars? Would it be possible to drill and tap the blanked area where the RR sender goes in the later cars?

[HealeyV8]

I have the rover v8 installed in a 1970's car with smiths gauges. I found that my temp gauge plays up if the engine earth strap needs sanding.
Easy test get a jump cable from the earth on the battery and clamp it to the nut part of the sender when engine hot and if gauge moves that's your problem.

[KugaWestie]

Well ETB advised me that the sender they sell is not compatible, but they did give me a part number for one they said would be. So I ordered one and it arrived today.

Before fitting it I decided to test it.

I temporarily connected the top of the new sender to the sender cable that goes to the gauge, earthed the body with a temporary wire and then suspended it in a mug of hot water with a digital thermometer also in the water.




Then I turned the ignition on and took a look at the gauge.




Here it is fitted in the Range Rover sender location.




That looks like a winner to me, I will report back again once I have road tested and cycled the fans.

[KugaWestie]

Test drive tonight had the car sitting at about 80c when running along at 60mph, rising to 90c in traffic at which point the fans kicked in.

So all good.

If anyone needs the part number for the sender, it is Lucas SNB108

[andrewbr]

Thank you for doing this investigation and testing, I'll have to check if my car has the spot for this new sender (I suspect not - pre-serp engine), but it's good to know for the future.