Odd Coolant gauge behavior

[tom4motion]

Evening everyone,

My RS6 has developed a strange issue over its winter sleep.

Driving it to its MOT this morning I noticed the temp gauge didn't move at all, but the oil temp did rise to what I would expect.

After the MOT I had a look on VCDS and found no error codes in the engine or instrument modules, Engine G62 coolant was showing 92⁰‐96⁰.

When I looked in the instrument module, the coolant temp was showing -50⁰ . I've done the analogue dial test and the temp gauge moves so that's working.

Does the RS6 have 2 separate coolant probes, or are the combined into 1.

Also, where is/are the probe(s) located in the engine bay?

Cheers, Tom

[Ranger4130]

One here




And another here



Couldn’t say which is which but I would guess the second would be the temperature sender for the gauge.

Next time I’m in the engine manual I’ll take a looksie and see if it states which sensor does what.

[Ranger4130]

Didn’t take long. Engine coolant sensor

[tom4motion]

Ranger4130, thanks for that

Actually looks relatively easy to get at both.

Out of interest where did you get the repair manual from?


Cheers, Tom.

[Ranger4130]

Yeah doesn’t look too bad at all right at the front on top. I’d rather be changing that then the AC compressor and engine mounts.

Manuals.... I got them from a website. Cardiagn or something.

https://cardiagn.com/audi-a6-4f4f24f54f ... -diagrams/

If the link doesn’t work send me your email and I’ll forward them onto you.

[tom4motion]

I don't suppose anyone knows the part number for the sensor in the 1st pic by the oil filter?

Tried looking on the online ETKA and even phoning Audi with no luck.

Cheers, Tom

[IanH755]

That unplugged one in the centre of the top picture next to the oil filter housing is the Fuel Low Pressure Switch G410 - item 13 in the top right of the diagram - with it's vertical metal bracket on the outboard side, small hose behind it and black plastic hose clip above/behind it with the hose following the same route as the diagram.

Item No - 6E906051K

G410 location in Workshop looking from behind and facing forwards so you're seeing the back of the filter housing and the two big plugs that you can see in the top picture posted by Ranger 4130 above -



The only Coolant Temp sensor is the G62 sensor which was in the second pic and has already had it's info posted by Ranger4130.

[adamfraser]

Hi Tom,

Wondering if you managed to get to the bottom of this? I was driving mine tonight, was sitting about 70 degrees then dropped to 50 - got it back home and there is definitely heat in the engine, but dosen’t seem to be showing a temperature.

Will get the computer on it tomorrow, and also going to check the resistance across the sensor.

EDIT - went out this morning and it all seems fine! Strange. Going to get the computer on tonight and try pull some live temperatures to see if it correlates.

[tom4motion]

Hi Adam,

Mine appears to of fixed itself now as well, the G62 and instrument readout on VCDS now match.

Maybe it didn't like being in a garage for 6 months.