Astra temp guage problem ,please help

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Sun 4 Feb 2007 20:40
Astra temp guage problem ,please help - ragla
Hi everyone ,new here and need your help/advice please help if you can ,thank you

I have a Astra 1.6 mark4,the temperature guage never moves .........unless I put the air/con on for a second then off again..................then the guage moves up to just off the bottom marker ,nothing more

The engine is getting hot though as the heater is working very well

please advice,surely this isn't normal?

I don't do long distances (maybe 15/20 miles) but as I say the engine does get hot,...............how come it's not registering ,do I have a fault /problem ?

thanks in advance
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Sun 4 Feb 2007 21:47
Astra temp guage problem ,please help - milkyjoe
could be a fualt with the temp sender on the thermostat housing or poss a faulty thermostat stuck open, is the top hose to radiator getting hot?
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Sun 4 Feb 2007 22:42
Astra temp guage problem ,please help - ragla
thank you for your reply milkyjoe ,yes it is getting hot
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Sun 4 Feb 2007 23:44
Astra temp guage problem ,please help - Dynamic Dave
Well if the fuel guage is behaving itself (they share the same voltage regulator in the speedo housing) it sounds like it's the temp sensor under the bonnet at fault - or the wire(s) going to it have become disconnected.
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Mon 5 Feb 2007 00:14
Astra temp guage problem ,please help - milkyjoe
disconect the temp sender connection and earth the wire to the cars body or bare metal with some copper wire ,if the temp guage now reads hot then you will have to change the sender, let the engine get hot before you try it tho
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Mon 5 Feb 2007 10:09
Astra temp guage problem ,please help - Dynamic Dave
let the engine get hot before you try it tho


Can I ask why?

:edit: If the guage is working, then shorting the sensor wire to earth regardless of whether the engine is cold or hot will still make it go full scale.
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Mon 5 Feb 2007 13:17
Astra temp guage problem ,please help - Number_Cruncher
Please forgive my pedantry Dave,

Shorting directly to earth should make the gauge go beyond full scale.
Shorting via a 100 Ohm resistor should make the gauge go to full scale.

Number_Cruncher
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Mon 5 Feb 2007 13:37
Astra temp guage problem ,please help - Dynamic Dave
Pedantry forgiven NC ;o)

However, how can a gauge go beyond FSD if the needle has already reached the limit of it's travel?

I can see what you're trying to get at though. Using a 100 Ohm resistor limits the voltage to the gauge.
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Mon 5 Feb 2007 13:57
Astra temp guage problem ,please help - Number_Cruncher
Taking a Vauxhall petrol gauge for example, the needle can physically go beyond the full marking on the scale before it hits a physical stop, and this is what you would get if you short the sensor lead directly to earth.

Using the 100 Ohm resistor, should put the needle exactly at the full marking on the scale.

I suppose that for many meters, the physical stop is at full scale, and so, full scale deflection and hitting the stop is one and the same needle position.

Number_Cruncher


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Mon 5 Feb 2007 10:25
Astra temp guage problem ,please help - ragla
I will try this and let you know .........thanks to both for your help,very much appreciated
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