B8 S4 Coolant temp sensor location?

[comp80]

My S4 is throwing a temp sensor intermittent error in VCDS, and while the part is easy/cheap to obtain, finding it's location certainly isn't!

Before I pull my engine to pieces hunting, would anyone know it's location? I am expecting a easy-to-replace, but hard-to-reach location!

Thanks in advance

[theweebabyseamus]

It’s right in the front of the engine. Somewhat under the supercharger pulley area, where the two parts of the coolant pipe meet. You’ve probably already seen it.

[comp80]

It’s right in the front of the engine. Somewhat under the supercharger pulley area, where the two parts of the coolant pipe meet. You’ve probably already seen it.

Thanks so much, will have a look at it later today.

[comp80]

So I found the offending part, and was about a 3 min replacement job. Took longer to top the water up than to replace the sensor!

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But...

Still hasn't solved the running cold problem. When sitting at idle, will get to around 70 degC, ('normal' is 90degC), and then drops down to about 50ish when driving. Only time is raises up again is if it's sitting in traffic or not moving.
Would anyone have any suggestions at to what could cause this? My first thought was that the thermostat is jammed open, but it was replaced last year (due to overheating!), so that's less likely, but still possible I guess.

[theweebabyseamus]

Replace the thermostat again. I had a similar situation, and I’m not the only one.

[comp80]

Replace the thermostat again. I had a similar situation, and I’m not the only one.

Well, you can now add me to the list!
After changing the sensor, and making no difference to temps, took it in to my local Audi. Apparently the parts from last year have a 2 year warranty that includes all the labour (phew!) So after a bit of analysis, they spent the day yesterday replacing the thermostat.
Now have a perfectly working 'hot' car. Excellent!