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Discussion Starter · #1 ·
Hi Guys & Gals,

Strange one. The temp gauge is completely erratic. Either while I'm driving or just running on idle parked up the temp gauge will shoot up to 130c and then back down to where it should be at 90c

I have changed both the temp sender (sensor) and also the thermostat, so it is not that.

The link is a download 123MB but is safe and shows you the issue. I can drive for a while with no issues for a while even while hot and then it just does it's thing. Any ideas will help. thanks


Cheers
Andy
 

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VR6 GT35 4mo
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Use VCDS to verify actual coolant temp. It's not the stat.

Either cluster is dead or wiring is dead. If you disconnect the temperature sensor, do you have the same issue? Did you actually chance the temperature sensor? Not patronising here, but there have been instances where people have changed the rad switch.
 

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Discussion Starter · #3 ·
Use VCDS to verify actual coolant temp. It's not the stat.

Either cluster is dead or wiring is dead. If you disconnect the temperature sensor, do you have the same issue? Did you actually chance the temperature sensor? Not patronising here, but there have been instances where people have changed the rad switch.
Cheers for the reply Adam, I really have changed the temp sensor but not tried disconnecting the sensor to see what happens. I will try that.

When you say "Use VCDS to verify actual coolant temp. It's not the stat" what do you mean for stupid people :) Also what is a rad switch?

this link is the same temp sensor I have changed (Twice in 2 years but that's another long story)

 

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The only time I had a similar issue was when coolant leaked from my temp sensor into the wiring loom. My temp would drop from 90 to 0, then jump around and settle again.

New sensor and drying out the plug solved it for me, although the coolant had made its way further down the loom too.
 

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VR6 GT35 4mo
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It's quite common to get a leaking sensor and the coolant rots out the harness.

I mean the sensor is two parts - the ECU sees one and the cluster the other. Use VCDS to see if it's swinging about too, although your idle doesn't look like it moved so I'd say it's not.

It's not the stat - it just couldn't operate that quickly to make the temperature do what it's doing. It's an electrical/wiring/sensor/cluster fault. Not mechanical.
 

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Discussion Starter · #6 ·
Thanks for that info. I have a multi meter with temp setting so I will test the actual water temp when it does that but suspect like you say it's not mechanical. I will check out the wiring as much as possible and also see what happens when unplugging the sensor.
 

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Discussion Starter · #7 ·
So, managed to spend a little time looking at the problem. I'm now also getting the code P0171 - Bank 1 Lean, so now it's even a bigger issue. Could be MAF or leak in hose. Temperture of the water does not go above 90c, Wiring looks fine
Going to investigate more tomorrow
 
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