Temp gauge

**dreddfan** · 18-10-2012,03:19 PM

My temp gauge on the dash has stopped working recently.
Does anyone know where i should start looking for a probable cause? I've seen online that the coolant temp sensor in the B5 can be weak and prone to failure. Where is this sensor mounted in the engine?

Any help would be welcome.

MS.

**avant adam** · 19-10-2012,11:44 PM

I thought I had this problem too. Turned out I was just a little low on water and the outside temp is cooler too so it's not getting that hot. Sits below 70 degrees all the time now

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**Doctle Odd** · 20-10-2012,12:59 AM

70 degrees is far too low for the car to run efficiently. I usually have a spare coolant temperature sensor, they are known to fail and a genuine VAG one isn't very expensive. It's on the pump side of the engine behind the crankcase pipe 4 wires going to it. It can be blue, green or black in colour. It's held on with VERY easily broken clip but if you buy one it won't break. Sods Law! drain a couple of pints of coolant with the engine cold its a 10 minute job

**Randomhedgehog** · 20-10-2012,07:34 PM

If the gauge is still moving a bit but not showing as up to temperature on a run, such as it only reaching 70, it may be the thermostat is stuck open. If you set the climate control to diagnostic mode on channel 49 you can read the coolant temperature direct from the sensor which may help narrow down the problem.

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**dreddfan** · 22-10-2012,09:12 AM

Thanks for the info.
I'll ring the local dealer and get a price on the sensor. Anyone have a part number for it?
I've also noticed my electric heated wing mirrors are always on as well, could this be related??

**Doctle Odd** · 22-10-2012,09:40 AM

No part no off hand but engine code will get you the correct sensor

**dreddfan** · 26-11-2012,12:02 PM

I finally got around to getting the sensor and installing it but i still have the same problem.
I'm now looking at replacing the thermostat but I have like to find a how to guide for this job.
Anyone know where I'd get one?

**HAWKS** · 26-11-2012,04:58 PM

What Audi is it... ive just rang Preston Audi for a quote to replace my thermostat on A4 2.5tdi Q. £708 + VAT This includes cambelt kit+stat(28+vat)
I am in the process of having a remote stat housing made. I will keep everyone posted on here.

**dreddfan** · 10-12-2012,03:36 PM

Its a 99 A4 B5 1.9 tdi.
Still looking for a good 'how to' for this job if anyone knows where I'd get such a thing.

**jas828** · 10-12-2012,04:57 PM

done mine other day mines fitted with afn 1.9tdi engine and it was down below alternator exiting engine behing angled plastic water stub needin 5mm allen key to remove 2 bolts and then remove plastic stub and there will be o ring and then thermostat dont forget to drain coolant first and if you not reusing coolant you will g12 do not use blue or green as they will react with existing coolant