Vauxhall Astra E - Temperature Gauge Going up and DOWN while driving

Honest John Back Room » Technical matters
View Threaded
Mon 15 Nov 2010 11:23
Vauxhall Astra E - Temperature Gauge Going up and DOWN while driving - Astra1979

While driving my Temp Gauge goes from zero upto just over 80 and then drops back down to just above the two white notches at the bottom (far left) of the gauge.

It keeps going up and down like this while I'm driving.

I've had my car MOT'd at a Vauxhall dealership and mentioned this problem to them at the time. They said they've ran a diagnostic on it but found no fault so to just ignore it.

I'm positive it used to stay between 80 and 100 when the engine was running.

Any advice on this (potential causes, problems it could cause if ignored, previous experience) or at least someone to say it's not normal would be great.

Reply | Report as offensive | Link
Mon 15 Nov 2010 11:28
Vauxhall Astra E - Temperature Gauge Going up and DOWN while driving - injection doc
does the fuel gauge alter even by a smaller degree ? apart from the gradual decline ! then it could be voltage / instrument related
Does the heater fluctaute in its output ? if so it could be thermostat related,
if the gauge fluctuates more in this cold weather its more than likley stat related.
easy to diagnose with live data from engine temp sensor.
Worth getting checked because if its a stat then you will use more fuel than neccesary
Reply | Report as offensive | Link
Mon 15 Nov 2010 11:43
Vauxhall Astra E - Temperature Gauge Going up and DOWN while driving - Astra1979

Thanks for the quick reply.

The fuel gauge is fine. Not sure If i'm imagining it but I seem to be using more petrol than usual.

The heater output is fine as well.

Thanks for the advice, will definitely be taking it back in. Just glad I'm not imagining it as being a problem

Reply | Report as offensive | Link
Mon 15 Nov 2010 12:09
Vauxhall Astra E - Temperature Gauge Going up and DOWN while driving - madf

They said they've ran a diagnostic on it but found no fault so to just ignore it.

Hmm.. Thermostat problems do not show up in dignostics.

Guage problems do not show up in diagnostics.

Temperature sensor problems do not show up in diagnostics.

Wallies..

Reply | Report as offensive | Link
Mon 15 Nov 2010 12:44
Vauxhall Astra E - Temperature Gauge Going up and DOWN while driving - Astra1979

I didn't know that Thermostat problems, Temperature sensor and Guage problems didn't show up.

Thanks for the additional info and another quick reply.

Reply | Report as offensive | Link
Mon 15 Nov 2010 18:10
Vauxhall Astra E - Temperature Gauge Going up and DOWN while driving - elekie&a/c doctor

Check the wire that runs to the temp gauge sender (blue/white wire).If I recall ,this wire had a habit of rubbing through the alternator bracket.hth

Reply | Report as offensive | Link
Wed 17 Nov 2010 13:43
Vauxhall Astra E - Temperature Gauge Going up and DOWN while driving - TeeCee

Sticking thermostat?

I had that behaviour on my Zafira when I first got it. Turned out that the thermostat had a slight tendancy to stick open (tired spring), so it would open when hot, stay open too long, allowing the engine to overcool, then close and repeat this cycle ad infinitum.

I replaced the thermostat, which cured the problem. The fact that you're seeing it only get up to 80 when it used to sit between 80 and 100 would also point to the thermostat spring being past its best.

Reply | Report as offensive | Link
Wed 17 Nov 2010 22:26
Vauxhall Astra E - Temperature Gauge Going up and DOWN while driving - madtaz72

hi there ive had this problem once and found that the themostat got stuck open ive had mostley caverliers and astras for 15 years 8v engines best to change themostat and also cheak the water pump undo the top of the exspanshion tank cap and watch to c if the water is flowing back to the tank on a small pipe if flowing ok then the pump is working fine if it is returning very slow then the pump could be on its way out because the themostat carnt work propley if the water pump carnt pressurerise the system propley ALL WAYS CHEAK FROM COLD THEN U WONT GET BURNT if not that cheak the little sensour with a cable on the themostat housing these very realy go good luck if get stuck drop me a message i be glad to help u madtaz

Edited by madtaz72 on 17/11/2010 at 22:29

Reply | Report as offensive | Link

10 warranty myths exposed

Here’s how to sort the fact from the fiction when it comes to car warranties.

Cheap Car Warranties

Looking for a garage you can trust? Honest John's Good Garage Guide has thousands of reader recommended garages, plus how-to guides and tips on servicing.

The Good Garage Guide