Hi all,
I've recently purchased my first mini, she's a 64 morris round nose. I've given her a once over with my mechanic mate and the only thing that i can't get fixed is the temp guage. I've searched and searched and i'm stumped...

The fuel guage, speedo and rev guage all work and is accurate. When I turn the ignition on the temp guage needle has a tiny little wobble and moves the smallest little amount but still doesn't even register as 'cold' (C on the guage). I've taken the plug off the sender and earthed it and it goes to up all the way so naturally i replaced the sender but still no difference. The sender is one from Global Spares they got in for me, see pics below. I also pull the guage out and checked connections and again, all good. I even swapped them around etc. but no luck. And last but not least, i boiled the kettle and tried both senders in the hot water, again nothing.....

Does anyone have any other theories.....?

Quick question, when you checked it in the boiling water did you earth the body of the sender?

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Check wiring from sender to gauge...
Try another gauge if you can...

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"Show me the Mini!"

When I earthed it in with the boiling water it moved ever so slightly but barely nothing at all...

I don't have a spare guage so I might need to buy another. I was under the impression it's working OK because when I earth the wire it goes to full noise?

Are you using any thread sealing tape when installing it into the block?
Does the speedo have a voltage stabiliser on the back?
What part number was the temp sender?

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I did have some tape sealant on it but removed it.
Will need to check for the voltage stabilizer but fairly sure there is one.
I will get the part number and post that when I get home tonight...…

Thanks

Having similar problems with my '66 rebuild.
Your gauge seems to be working - the ****** with ignition ON and earthing the lead.
I have bought several sender units; for minis 1964-69 (with voltage stabiliser) they are supposed to be GTR104 with a red identifying ring (where yours is white) - Smiths TT3802/00.
The first one barely moved to "C" even when hot. Tested the resistance of another one and there was a large difference - 2nd one reads much closer to "N" but still not quite right.
Other posts here have commented that there seems to be serious quality control issues with these sensors as they are all aftermarket replacements.

the white is actually a bit of tape I pushed to that spot to make sure it was earthing correctly. It didn't come with any colour identify ring. My next step was to purchase a GTR104 from minisport.com. I will check for voltage stabilizer tonight before ordering one.

I put a trimpot on the sender wire and calibrated it to read N at 180°F.
I don't think current senders are quite correct.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Any details on which type of trim pot? Jaycar sell them but they have a few different ones

See if you can find what resistance the sender is supposed to have at a know temperature (s) and this will tell you the resistance range you want. In your case your resistance is too high so you will need to put the trimpot in parallel I think, and this will reduce the resistance, the trouble is it's not the simple calculation it was for putting the trimpot in series.

https://youtu.be/VDVJYvrpP50

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Roads need more corners
A Deluxe(CG13DE), 2 Clubbies(998 and 1275) and 2 Morris 1100Ss

As a comparison - These are the readings from my car using the standard 10V temp gauge and a choice of new and used senders. Your readings will be different if your car is early 64 using 12v.

I'm not overly fussed about exact measurements as long as I get it reading where 'normal' is and then I can monitor if it jumps up to stop driving. Problem is I can't get a ready of anything. I will pull the dash out again tonight and check everything and take some more snaps to post while I'm there.

The gauge in one of my cars is accurate and in the other it is useless, my 2 cents worth get a mechanical gauge I have one in each brilliant!!

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That's why it's good to be.............ME

RT4350 I think. 200 ohm.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.