Contradictory Water

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Way2go
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Contradictory Water

Post by Way2go » Fri Jan 13, 2006 3:37 pm

Hi, Does anyone know what it means on a GTi when the red light comes on on the water guage but the temperature meter reads only 90 degrees? Water level OK and Heater temperature OK. Is this thermostat, sensor or something else? :cry:

Stewart (oily!)
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Post by Stewart (oily!) » Fri Jan 13, 2006 3:43 pm

The imperative STOP light is wired to come on when any of the other idiot lights come on, if the temperature gauge is working correctly then I think the red light is the other sender sitting on the the side of the block next door to it, it could be telling lies.
Stewart
TZD 19 TD one of the few
Xantia Td estate, going soft

jeremy
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Post by jeremy » Fri Jan 13, 2006 3:49 pm

The BX 19 instruction book states:
COOLANT TEMPERATURE
If the warning light comes on, together with the 'STOP' light, stop immediately but let the engine idle. then check the coolant level taking the precautions . . . Contact the nearest Citroen dealer.

Its commonly known as the TOO LATE light!

I'm not sure if it uses the same sensor as the gauge or another - if it uses the same sensor it would be likely that its operated by the gauge. Needs to be investigated - probably the best thing would be to ascertain what the temperature at the sensor actually is when it operates. If convenient and safe I suppose you could remove the sensor, connect it up again with an extended lead (needs an earth too) and boil it in water and see what happens. (eg using a gas camping stove or blowlamp and a pan)

jeremy

M

Post by M » Fri Jan 13, 2006 4:25 pm

jeremy wrote:Its commonly known as the TOO LATE light!
Or the Lamp Of Death :twisted:

If its just the red light, and nothing else it soundls like a faulty sensor or piece or wire... Out with the multimeter then - welcome to the wonderful world of Citroen electicals.... :D Does it come on all the time or just intermitantly / turning left/right that sort of thing?

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Contradictory Water

Post by Way2go » Sat Jan 14, 2006 3:05 pm

Thanks for speedy replies folks! I think I am getting closer to the source of the problem as although earlier I thought the cooling fans were working, on observing a heat up cycle on tick-over they never came on at all. The rad stays cool until the thermostat opens and then the rad becomes uniformly hot so presumably pump is OK too.
2 things puzzle me about this light though 1) Haynes says this light is triggered at 112 degrees C so why does the guage only read 90C. 2) If water is 112C as per light, why is there only the barest hint of pressure when the radiator cap is removed and why doesnt it boil over when the cap is removed cos surely the extra 12c over boiling should cause an immediate eruption when the cap is released ???

I will investigate the fan wiring when the rain stops and hopefully this will sort the main problem when I identify the cause but the temperature information that the car is giving above does not seem to make proper sense.

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Post by Stewart (oily!) » Sun Jan 15, 2006 3:18 pm

Sounds like at least one of the sensors is lying then.
Stewart
TZD 19 TD one of the few
Xantia Td estate, going soft

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Post by Way2go » Wed Feb 01, 2006 9:17 pm

Stewart (oily!) wrote:Sounds like at least one of the sensors is lying then.
Stewart
Thought that you may like to know that this turned out to be a case of "Don't shoot the messenger!"

Fans were OK and so was fan switch even though fans didn't run when engine overheating light came on.

Used Wynn's Professional Cooling System Flush and cycled it several times over a day until red light no longer triggered.

Heater now takes longer to heat up, temp guage rises more slowly to 90 and then temporarily falls back a few degrees when the thermostat opens and the rad fans now run slow speed for 10 or 20 seconds occasionally. 8)

I thought that the guage would alert me to overheating problems but it seems not in every situation :roll: