Coolant Temperature Sensor not working

[blairmrennie]

Hi Guys,

Looking for a bit of help with my 2.4 v6 b6 estate.

I have recently been having issues with my temperature guage being a bit erratic/not working at all. I have changed the coolant flushed the system through the best I can and had started looking at thermostat change but I believe it is a cam belt off job which is a bit above my DIY skill base.

I have a Bluetooth ODB II reader and Torque app and on a good run today the "Engine coolant temperature" was fairly steady around 90 degrees going up a bit in traffic and down a bit on the motorway.

In my limited knowledge i would say that the thermostat is not the issue and perhaps a temp sender (if my engine has 2??) Or a faulty dial.

So long story short. Could anyone help with a bit of knowledge around if the 2.4 V6 has 2 temps sender's, 1 for ECU and 1 for dash cluster.

Also, I have ready that I can enable a needle sweep using the diagnostic port and a laptop. Is there any recommendations for software and adaptor to let me do this. I work in IT so more comfortable with the tech side than the mechanical side to be honest.

Any help is much appreciated.

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[Stonedofmoo]

If it's like the TDI model, the coolant sensor itself has two circuits to send temperature information so you can have a weird situation where the sensor works on half the circuit only

Fit a new one, it's a cheap part and not very difficult to fit in most cases, just have more g12/g13 coolant ready as you'll lose some in the process. I'd imagine there are plenty of YouTube videos describing the process.

Change the thermostat at the same time, it's pointless changing one and not the other as you have to lose coolant in both cases

 

[Stonedofmoo]

Oh wow, intrigued I just checked the V6 model. You really do have to remove the cambelt, what a crazy design!!

 

[blairmrennie]

Oh wow, intrigued I just checked the V6 model. You really do how to remove the cambelt, what a crazy design!!

Yeah all my previous cars had the thermostat in an easy to reach location. Was always a quick fault finding step.

Not quite so quick with this V6.

Cheers for the reply I will see if I can get the model number for the temp sender and get one coming.

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[mr_pepps]

Hi @blairmrennie - I had a coolant temp sensor fail in my ASN 3.0V6 A4 cabriolet. I battled long and hard to get the thermostat off - had to remove all pipework and the inlet manifold before the thermostat housing would budge because it sits bolted down under the corner of the IM.
If I were you I would simply replace the coolant temp sensor (little green one I think) at the rear of the engine bay. Reasonably easy to access. This cured my issues - my dash temp gauge would go to 90 and then blast all the way up off the scale. Then it would drop off completely and finally bounce back up to the top again. All very disconcerting - I did the same as you and ran a live diagnostic tool to monitor temperatures. Readings sat within the 89 to 96 degrees. All normal.
The replacement sensor fixed everything.
My adventures with the inlet manifold came good in the end - but because it was winter time last year and I don't have a garage it took a long time stealing an hour here and there after work.....

Best of luck.