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My Mk1 Cooper s temperature gauge is reading high.. The engine is not overheating. I have been trying to find a correct cooper s sender unit. I have tried various ones that say they are for an s but no joy.GTR 101 and GTR104 but still the same.
I have changed the voltage stabiliser but still the same. I am running the car in at the moment. No water loss or boiling and heater is blowing warm air.
Does anyone have a genuine cooper s sender unit
Regards Brian.

Which gauge do you have? Stabilized or non-stabilized?

I believe Brian said he replaced the stabilizer. However, 1964 was a transition year for the gauges so it is important to know all the components can work together.

Brian, can you post a picture of the back of the temp gauge?

Thanks for the reply. I have posted a photo of the back of the gauge.
Regards Brian

I dont know if that file worked so i have tried another
Brian.

That's a stabilized gauge. GTR104 should work. Can you test it out of the car to isolate "other" possible issues?

Ricardo,
Thanks for the reply. I have tried so many senders and they are not all stamped I think I will purchase another GTR104. I had another temperature gauge and fitted that and it is doing the same reading high. I will start at the basics ensuring the sender I am using is a 104. If that fails I will try what you suggested.
Thanks for your help and I will come back and let you know what I find.
Regards Brian.

Ok, make sure no wires are touching around the speedo where the stabilizer is mounted.

Try running a separate wire direct from the sender to the gauge, or, stabilizer, just to eliminate any possible grounding in the wiring harness.......

As others stated above, that is a stabilized gauge and reading high MAY be due to a stabilizer ground issue. With stabilizer problems both the fuel and temp gauges should show similar behavior.

If the voltage stabilizer looses its ground it will pass full charging system voltage to the temp and fuel gauge. That means those gauges could read as much as 40% high. Check that the stabilizer mounting tab has a good ground. Also inspect the stabilizer. There is usually a thin copper strip pinched between the stabilizer case and circuit board. If that connection gets dirty/corroded the stabilizer can lose its ground.

Solid state stabilizers are available in both positive and negative earth. They are a nice solution if you determine it is the stabilizer itself.

I’ve found over the past 5 or more years none of the new senders are right.

For now all I can suggest is a gauge matcher

Thanks for the help so far. I now have a few different things to try and I will try these and come back with the outcome
It’s appreciated
Brian

I tried a few things today. Checked and cleaned round the area where voltage stabiliser sits and checked for proper grounding. Tested but still reading high. Run a temporary cable between sender and gauge. No change.
Replaced sender with one I had and put in an 82 degree stat. Gauge is now showing between Normal and High. I could accept this but still feel that sender is the problem. If anyone has a mk 1 coopers sender for sale or equivalent I would purchase. Have tried various places and purchased but I think they are all being manufactured from the same place.
thanks again for the help so far

Hello Brian,
From my experiences with temperature gauges not behaving. I took 2 gauges and senders to my local
instrument repairer who serviced both of them. They are both working accurately now. There is some calibration
of the gauge itself using the little white dots below the C N H and a special tool is used to adjust this so he
explained. Just a thought for you to consider.
Regards,
Glen

Hello Glenn
If I could find the right company I would send the sender and gauge to get calibrated or matched. I would appreciate an address or email
Thanks Brian

I've sent a PM Brian
Glen

I managed to find an original temperature sender unit for my mk 1 Cooper s engine on ebay in its original sealed packing. Fitted it today and gauge sitting on normal.Problem solved.
Thanks for the replies and help
Brian.