Jump to content

water temp gauges


white90

Recommended Posts

It isn't Tony, only the capilary presure guages pipe hot fluids to the dash, the capliary/mechanical temperaure guages do not. The temp is read at the 'sender' which is meachanically (rather than electrically) connected to the guage.

Link to comment
Share on other sites

It isn't Tony, only the capilary presure guages pipe hot fluids to the dash, the capliary/mechanical temperaure guages do not. The temp is read at the 'sender' which is meachanically (rather than electrically) connected to the guage.

correct; you can unsolder the knob-end (pardon my French) fitted on the copper tube for oil pressure guages as this came loose on mine and also when I shortened the tube.

the capillary temp guages have a bulb filled with something mysterious - I have heard it is a freon type liquid with a large coefficient of expansion (and also heard it is mecury - don;t believe that one). Inside the guage there is a small bellows that pushes on the needle. As the termperature of the bulb inscreases, the fluid inside expands making the bellows expand which pushes on the needle.

the advantage of electic gauages is you can relocate the gauage easily - all it needs is to disconnect the wires, not so with capilliary as you need to undo the gland holding the bulb in the cylinder head.

advantage of capillary type is they show a reading when there is no electrical power and have the needle pivoted in the centre of the gauge, whcih looks far nicer (there are only 2 electrical guages that have that layout - I can dig out details of those if you want).

Link to comment
Share on other sites

advantage of capillary type is they show a reading when there is no electrical power and have the needle pivoted in the centre of the gauge, whcih looks far nicer (there are only 2 electrical guages that have that layout - I can dig out details of those if you want).

The main advantages of of the capilary guages is their accuracy and reliability.

No sender/guage matching or electrical gemlins to worry about.

Also the single capliary guages (not the duel display ones) tend to show the range over 270° of the dial, where as the elctric guages show the range over 90°, so the display resolution on a capliary guage is often 3 times that of the elctric guages. Although even teh dual capilary guages show the range over 180°. This is certainly true of the Racetech guages that i use, and also may other makes too.

Link to comment
Share on other sites

Tony, won't you want electrical on a 300tdi as that's what you'll have at the moment? I need to sort a decent water temp gauge too; I'm not convinced I get anything like a realistic reading with the standard one.

Who cares about the actual temperature the engine is running at? As long as the needle is in the usual place on the guage then there is nothing amiss. If it starts reading high or low then there is a problem.

TC, As mentioned above, there is a bulb filled with, IIRC, some sort of alcohol which expands when it gets hot. This expansion moves fluid up the capiliary tube to the guage where it acts on a device a little like a barometer - often coiled like a snail shell - and moves the needle more as the alcohol expands more. In the unlikely event of the capiliary breaking at the guage end you will get a small amount - no more than a couple of CCs - of hot alcohol released as it escapes from the bulb in the water.

Chris

Link to comment
Share on other sites

Who cares about the actual temperature the engine is running at? As long as the needle is in the usual place on the guage then there is nothing amiss. If it starts reading high or low then there is a problem.

I care. If the guage moves above normal then I like to know how much above normal it is so I can make a more informed decision about what action to take - carry on / ease off / stop / get the fire extinguisher out.

Also with the higher resolution of the dials on the capilary guages it is much easier to see the needle move off normal as you get 3 times the movement.

Link to comment
Share on other sites

Well I went for a computer controlled gauge.

A full 270 degrees needle movement.Nicely lit.A max temperature warning light.

I bet it's a bit pricy for most people.

Have a look at www.SPA-UK.co.uk at the analogue gauges.

I eat rat poison

mike

I can cause trouble in an empty house !!!

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We use cookies to ensure you get the best experience. By using our website you agree to our Cookie Policy