GolfGTIforum.co.uk
General => The garage => Topic started by: gibby on 11 March 2005, 00:06
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Over the last five days my temp light has flicked on and off while driving three times, I've topped up the coolant and I've checked the fuse for the fan and that's ok and works. Is there anything else that might cause this or is there anything else for me to check ?? :undecided: The car is not overheating and the oil temp is running normal.
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have you got braised hoses running across the engine for the fuel injectors?had this problem with mine.found out the braised hoses were rubbing on the rocker cover causeing a short with the temp light.
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Thanks eyelet, I'll check that out tomorrow. :smiley:
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I will take it you mean the red light in the temp gauge.If the gauge is reading normal its low water level low.If the level is spot on, then possible sender fault in the expansion bottle could cause this.
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Can also point to incorrect antifreeze mix. Next time it does it, take the plugs off & bridge the pins, if the light still doesn't go off you have a wiring problem. If it does the sender has had it :)
Take it out and give it a good clean then see how you go.
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How does the sensor measure anti-freeze concentration?
Thats a new one to me ?:laugh:
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It changes the conductivity of the coolant mate ;)
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Ok, never seen that happen before.
I'll just have to take your word for it :wink:
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How it actually works is the sensor has to metal prongs that go in the water, water conducts, so this makes a circuit, light stays out.
If water does not cover the 2 prongs then no circuit so light comes on.
I don't think it has anything to do with antifreeze concentration :wink:
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Antifreeze
Antifreeze is a substance which lowers a solution?s freezing point.? It removes ice or prevents ice from forming.? It also prevents freezing in planes and automobiles. Antifreeze is also used in refrigerants and as heat-transfer fluids.? Ideal antifreeze should be chemically stable.? It has low viscosity and electrical conductivity and a high boiling point.? Automobiles operate at an extreme temperature, therefor it is cooled by liquid that circulates through the cooling system.? Antifreeze is noncorrosive and has good heat transfer properties.? Most antifreeze is used in cars today.? It is composed of methyl alcohol, ethyl alcohol, and ethylene glycol.? Also most antifreeze have phosphate nitrate, or another anticorrosive agent.? Some time ago kerosene, honey, salt water, and methyl alcohol were used as antifreeze.? Automobile antifreeze is a well-known poison.? The sweet taste appeals to most animals, like cats and dogs.? Consuming even a small amount may result in death for small pets.
:wink:
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Totally irrelavant mate.
Water will conduct, does it not? :wink:
After all you wouldn't drop your toaster in the bath would you? nothing to do with antifreeze :laugh:
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The sensor in the expansion tank is a level sensor, it will not tell you if the coolant mix is wrong, it will tell you when it is low.
Steve
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Cheers Steve, thats what i was trying to say all along, but it fell on deaf ears :laugh:
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It does also monitor the antifreeze mixture!
http://www.eurocarparts.com/forum/topic.asp?TOPIC_ID=4986
http://www.performancevwmag.com/forum/topic.asp?TOPIC_ID=24567
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Ok, sorry, its on a couple of forums, so it must be true ?:laugh:
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Did you notice how the first guy solved his temp light problem just by replacing the coolant? Think what you like, I'm sure the sensor also monitors the antifreeze concentration. The only thing I'm not sure of if its all MK2s that do it or only the late ones with the round expansion tank.
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thats a new one on me also
didnt do it on my late 16v (round bottle) and doesnt do it on my current 16v (early bottle)
and my late 16v was running on pure water at one stage!!
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I was thinking along the lines off if you had too much antifreeze it would flash, as the conductivity would be too low? You don't want to be running too much antifreeze as it is less efficient at transfering heat than water.
I'm doubting myself now, if only I had a level sensor to do some testing with :grin:
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Yes Rubjonny, that is correct.
Too much antifreeze will probably make the light flash, but it would have to be virtually 100% antifreeze ?:laugh:
This is because antifreeze is actually a poor conductor.
So you are now infact contradicting yourself ?:evil:
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Mate why don't you read my post again starting from the top left and working through every word till you get to the last full stop, that is exactly what I just said :grin:
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The only way that the light will come on is if you are using virtually neat antifreeze. Is anyone actually stupid enough to do that?
So no the sensor doesn't actually measure concentration at all, only it will stop working if you use pure antifreeze.
Read through my posts again, thats what i keep saying.
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I know and understand what you are saying. My point is that perhaps the sensor can detect a drop in conductivity, if there is enough then the light flashes to warn you. Very much like how a temperature gauge can measure a range of resistance values from a sensor, they dont work as a simple on/off switch do they? But this is only a theory I came up with to explain how it might work if the tank sensor can measure antifreeze concentration.
Of course I might be wrong and it could be as you say, I have read posts from other respected forum members that the light will warn you about an incorrect antifreeze mixture. I havent seen it mentioned if it is supposed to warn you if there is too much antifreeze or too little, or both, just 'incorrect' ;)
I didn't really want to turn this into an argument to be honest, so lets just leave it at that eh? :)
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Like i said before, i wouldn't believe alot of things i read on internet forums.
Some people on these respected forums have never got their hands dirty in their lives.
Whatever works for you really, thats what matters ?:cool: :laugh:
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The coolant sensor is just a level sensor, its not like a temp gauge, it doesn't read variable resistance.