Water temp. gauge/sender question

[ian]

Hi folks. I'm not convinced that my water temp guage is reading accurately. It is a Smiths unit from a 1974 XJ12, and the sensor is an electric one as opposed to the capillary type. Problem is that I have used a standard Chevy sensor, screwed into the inlet manifold. I suspect this isn't compatible with the Smiths gauge. When the engine is about to boil over the gauge indicates normal. There are no numbers to indicate actual temperature. How have other Smiths gauge users got over this? If I buy a Jag sender how should I fit it to the inlet manifold? Thanks for any tips. Ian

[maxGD059]

Aaaaaaaaaaaaaahhh!
Ian, don't trust any old gauge/sender. I've been trying to sort mine out for yonks! (see 'wetter water' post earlier this month.) Plumb everything in & get a digital thermometer from Maplin for a tenner & check the temp then make allowances for your gauge

Cheers

Richard
(Hillclimb convert)

[nbracken]

Ian, couple of suggestions:
- I use the Smiths sender to match my Smiths guage fitted to the Chevy inlet manifold via an adaptor - easy enough to make.
- to check accuracy a friend of mine has access to a digital infrared temperature gun which you pint at any surface and it gives you the accurate temperature at that point. I measured my oil temp in this way by pointing the gun at the sump right next to the sender and did the same with water temp on teh inlet manifold.
- another way to check temperature is to boil a pan of water and use it to check the accuracy ofthe guage by immersing the sender.

HTH

[Steve Faithful]

Ian if you got anything out of a chevy sender and a smith gauge
you are doing well.
I get nothing out of a similar set up.
as you I will be changing the sender to the standard smith unit
just need to turn an adapter to fit both threads.
best of luck
steve

[ian]

Nigel, Steve, thanks for the tips. What did you use to make up your adaptor? I thought of drilling out the centre of the Chevy sensor and tapping it to fit the Jag one, could be tricky though. Do you know of anything off-the-shelf? Thanks again. Ian

[ian]

I should have asked, do you know what size/type the respective threads are ie the Chevy sender and the Jag one? Ian

[nbracken]

Ian, sorry I don't know. I built my car between 91 and 94 and unfortunately didn't keep a record. If you have the Chevy sensor and also the Jag (or Smiths) sensor (which is smaller) you should be able to ve both to a competenet machine shop and they will be able to make you up an adaptor I am sure.