I always thought the mechanical gauges were more accurate, but could be wrong.
All I know is the electric oil pressure gauge in my Jag is a joke. About as useful as a screen door in a submarine.

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1967 Cooper S - new front bearings to do.
1965 Cooper S shell - all painted up, ready for fit out.
1969 Cooper S Mk2 - claimed by 2nd. born
1966 Deluxe- next rustoration!
Mk 2 & XJ6 Jags. Less said the better.

You could test temp with thermo gun, check on nut part of sender then read guage. Should be pretty close to same, don't stress if its a bit out.

Good thing about the mechanical is that it shows the temp even when ignition off......

But you can also see the temp rise when you switch off the motor.......

Zapped the sender and checked the guage and it seems to read low and slow to move up with the temperature.......

Will fix my radiator problem and re-check this way again.

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Cooper S Mk2
Cooper S Mk1
ex Cooper S Mk2, various Morris 1100s, 1300s, 1500s, Leyland Sherpa!

Fixed my radiator problem and now the gauge is completely dead.....reading nothing and engine is at around 80C when warmed up.....

Removed head adapter and fitted spare temp sender from my Mk2.....

Time to fit an original Smith's temp gauge I have lying around... now to sort the bloody wiring first as need to make new connections unless I can find loose wires in the dash somewhere....

Never ending........

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Cooper S Mk2
Cooper S Mk1
ex Cooper S Mk2, various Morris 1100s, 1300s, 1500s, Leyland Sherpa!

The mechanical gauges often have a big clearance between the tube in the head and the sensor. That air gap can delay their response. I have added some thermal coupling paste to mine. You can buy it from Jaycar. It is used to get heat flow from the chip to the heat sink.

M

Pulled the mechanical gauge out completely and when tested with hot water in the kitchen, works perfectly, despite not working in the car....
Tried to install electrical gauge but when tested, only reads N instead of hot when grounded to test....tried a brand new Mk2 gauge and same thing - only N and not H when grounded to test.
Checked power to fuel gauge and is 12V going in and 7V out where I was taking the power to test. Can't find any voltage stabilizer in the speedo area at all.......the mounting point is being use to ground the blinkers....
Tested my original Mk2 voltage stabilizer (now replaced with Wombat special edition) and is kaput as 12V in and 12V out at instrument lug.
Guess I will try installing a 10V stabilizer to power fuel gauge and temp gauge and see how it goes....
If needed, will re-install mechanical one and use thermal coupling paste as Mokesta recommended or failing that, buy a new mechanical one to save the stress and time.......

Hope this helps someone in the future and saves them a bit of time.....

Time for a beer......

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Cooper S Mk2
Cooper S Mk1
ex Cooper S Mk2, various Morris 1100s, 1300s, 1500s, Leyland Sherpa!

What is Wombat's special edition voltage stabiliser if it doesn't provide the 10v needed for the fuel gauge? Your temp gauge need 12v or 10v?

My Mk2 previously had issues with gauge readings so installed a wombat special in that car. The original stabiliser was still in that car but not connected, so I removed it and bench tested it, which apparently isn't that accurate. I will leave the Wombat special in my MK2 as gauges are reading fine in that car.

Wombat's provides 10v so guess I could temporarily remove and test in this car (Mk1) that I am now working on....

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Cooper S Mk2
Cooper S Mk1
ex Cooper S Mk2, various Morris 1100s, 1300s, 1500s, Leyland Sherpa!

Decided to use a mechanical temp gauge but would like your thoughts on the routing of the tubing.

I don't like them, especially in farenheit - bin it

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did I tell you that I won a trophy?

Why? and why? Just a personal preference? It was the unit of measure of the day when our cars were made. Do you like psi oil pressure gauges or metric? I used metric VDO's in my 7 clubman, but using round the dial "imperial" mechanical smiths gauges in the Mk2 S.

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1970 Mk2 Cooper S under restoration

Good one ausdino

Now to get back on track.
Decided to use a mechanical temp gauge but would like your thoughts on the routing of the tubing.

Are you installing the gauge in a standard deluxe/Cooper pod in the centre? If so there’s not many choices in terms of routing the tube. It makes sense to follow the oil pressure line or the wiring loom

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From memory, the smiths mechanical sender lead is long enough to follow the loom, under and across the slam panel and exit in line with the alternator to the head.
edited: found pic

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1970 Mk2 Cooper S under restoration