Temp Gauge Undereading , Is there a cheap temp alternative?

[terryp]

My cappillary temperature gauge has suddenly began to underead by about 30 degrees. I have checked the tube for any kinks and it is all OK.
I just wondered as I don't really want to start to drain the system and pay over ?100 for a reaplacment if there wasn't some sort of little Chinese gizmo that sticks to the engine and sends a signal to a digital display that could be mounted under the dash as a temporary measure?
Anybody with an eBay link or any suggestions??????

Thanks
Terry

[Spyder fan]

Terry,
Here's a good cheapie including the electrical sender the seller will post to Europe http://www.ebay.co.uk/itm/NEW-2-52mm-UNIVERSAL-DIGITAL-LED-WATER-TEMP-TEMPERATURE-GAUGE-METER-CAR-BLACK-/190995352666?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item2c7835cc5a

Or here's a capillary gauge at a very good price that you could use temporaryhttp://www.ebay.co.uk/itm/Analogue-dial-THERMOMETER-Temperature-Gauge-0-120C-water-oil-1-5meter-sensor-/200931734806?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item2ec876f516

Or maybe this boiler thermometer which runs off LR44 batterieshttp://www.ebay.co.uk/itm/Kesselthermometer-LCD-50-bis-150-C-Kabellange-1-5m-Digital-Fernthermometer-/200808896067?pt=Systemkomponenten_Heizung&hash=item2ec1249643

Happy bodging!

[billwill]

There is a high probability that your low reading is because you have lost some ether from the capillary system and now all the remaining liquid is vaporizing at the engine temperature so you are not getting the correct physics any-more which is supposed to be the vapour pressure in contact with liquid ether at the engine temperature and not the simple expansion/contraction of ether vapour alone.


The same happened to mine when I had a tiny crack at the bulb, which I have now soldered shut, but I have not yet gotten around to perform the tricky operation of getting some more ether into the bulb.

The usually mentioned people who can repair it for you are "Speedy Cables"

However you should first check with an independent thermometer or by putting the bulb in boiling water, that it really is under-reading and not some quite different engine problem.

[terryp]

Alan
Thanks for all those , I was hoping for a temp bodge that could be stuck on the engine rather than inserted into a hose (Thats too bodgey for me!)

Bill
Yes I think thats the way to go. I do think its under reading as I have a Cliveyboy set up with a Revotec fan controller that switches on at about 78 degrees (thermostat at 71 degrees) so I know the approx temperature.
There is a reconditioned one on Ebay at present for ?134 I wonder what Speedy would charge?

Thanks

Terry

[Spyder fan]

Hi Terry,
Speedy cables price list for replacement classic gauges here http://www.speedycables.com/smithminorgauges.html

You will see that their price for a new replacement gauge (although reading 0-100 psi for the oil) is around ?125 once you add VAT and carriage.

They can of course repair your existing gauge and it may be a bit cheaper than buying a new one, why not send them an enquiry or give them a call http://www.speedycables.com/enquire.html

email [email protected]
Tel: +44(0) 1639 732213 or 732299
Fax: +44(0) 1639 732238

[terryp]

Thanks Alan , will do, but I might wait until winter before sending it as the car will have to be drained

Cheers
Terry

[rgh0]

Just drain a little coolant to lower the level so you can pull out the bulb and put a plug in and also plug the oil pressure tapping. If you have confidence in the rest of your cooling system and oil system no problems running without the dual gauge for a while until it is fixed.

you will hear and see any problem before the gauges show it anyhow

cheers
Rohan

[terryp]

Thanks Rohan , I think it has to be a proper job.
I even have a temp oil pressure gauge I can fit.
I've emailed Speedy (Thanks Alan) and will do the right thing!

Thanks
Terry

[billwill]

Thanks Alan , will do, but I might wait until winter before sending it as the car will have to be drained

Cheers
Terry

No it won't actually.

In a plumbers such a B&Q you can buy a 3/8 closed brass cap which will cover the hole where the bulb temperature sensor goes and with a bit of effort you can probably find a similar one for the oil pressure monitoring hole in the block, though that is likely to be a threaded plug instead of a cap.

See the messages in page 7 of my long thread at:
lotus-elan-f19/getting-ogu-roadworthy-again-t26101-90.html#p176702

[terryp]

Just noticed something today. It doesn't exactly under read it just doesn't go over 50 degrees? What could be the matter? Anyone fix one ?
I had a quote from Speedy but I'm just trying to explore other options first

Thanks
Terry

[billwill]

Well it could be a rust speck or paint speck inside the actual dial causing that effect.
The gauge of a capillary gauge is actually a 0-100psi bourden type gauge, I think,

It gets 'straightened by the vapour pressure of the di-ethyl ether in the bulb and tube and on the end is a small lever which engages with a pivot arm to rotate the needle. A speck of rust or dust on those tiny gears could stop it rotating.


Typical bourden gauge

[terryp]

Thanks Bill, I will have a look and see.

Cheers
Terry

[billwill]

The gauges are not easy to open.

Ease out the tangs of the rim just a little, then twist the rim until the tangs line up with the slots, then ease the rim and glass off.

You may then need to undo various fastenings on the back of the case so that you can move the internals forward so that you can see them.

[terryp]

Bill
Just tried that and it all seems pretty loose. So it's back to speedy. Do you know what the female cap I need is (I would like to leave the male/male in the head)
I need it to be on EBay as we are in France

Thanks
Terry

[billwill]

I am pretty sure it is 3/8 inch

See:
http://www.ebay.co.uk/itm/BSP-THREAD-BR ... 2c5f95a171

and select 3/8

I don't know what you need for the oil-pressure pipe, sorry, but I think it has been mentioned on the forum.