Dash water needle gauge

Hi, another question, the dash water gauge one! does this show the temp of the water in the system, or the pressure?
i had a top rad hose split and the thin hose which goes from the expansion bottle to the rad also needed replacing, so i did both of these, however the plastic nipple on the radiator snapped off when removing the thin hose, have done a temporary bodge job just for a few days till i get a new radiator. Since all this has happened the water gauge on dash hasnt moved at all, thus thinking it has no pressure??

It measures temperature rather than pressure.  Check the wiring on the sensor -  it's easy to get at.

The problem could be in the sensor -  although unlikely: there is nothing to go wrong - but if it is the sensor you can get a new one from VW - ?17.64 part number 191498099BX

I am assuming the gauge worked prior to the top hose splitting?

Also when you replaced the coolant did you replace with the correct anti-freeze mix?  The sensor is sensitive to the correct anti-freeze/water mix - You should be using G12 from VW - comes in 1.5 litre bottles.  You'll need x2 plus 3.5 litres of de-ionised water .  The total capacity of the cooling system is 6.5 litres - drain off (by losening the bottom hose) replace - drive for a while - top up - repeat - and when the water level settles at the max mark you should be getting a reading on the gauge.  You will know early if the circuit is complete as you will have a flashing red light on the gauge on start-up - goes out after 30 seconds or so.

If this doesn't work, check the circuit back to the gauge - it will run through fuse - don't know which one - someone will - if this doesn't work then it could be dash-out - but if the gauge was working before the hose rupture I doubt the problem will be in behind the clocks.

M

Hey Loz636 - check this out:

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Current bid is only ?2

M

Thats brilliant thanks mike, i have got and fitted my new rad, also removed the fan bracket and de rusted and sprayed a nice aluminium silver!, the gauge now works fine, however i was told that it would be good to fill the cooling system with pure antifreeze which i have done without water, it has been running ok, temp on the mfa are between 94-108. though now u have said about the sensor being fussy about the right mix am wondering if it was a good idea?

Temp range is normal at 94 - 108 - perfect in fact.

Manufacturer recommends 40/60 down to -25C : 50/50 down to -35C I run mine on 50/50 - G12 from VAG and de-ionised water.

See 2.2 (5) of your Brown Haynes manual

I don't think pure anti-freeze will do any harm.  It is a corrision  preventer but will find any little leaks you might have.  If all is running OK, just leave it.  When you need to top up, use a little de-ionised water to dilute the eth-glycol

Glad you got it sorted.

M