dmanders

Just in the last week or so every time I start my 19 Q8 I get the warning in the subject line. According to the manual this means that fuel has made it into the oil and I need to get to the vehicle up to temp to burn it off. I have driven it as much as 10 miles without the warning going away. Do I have to drive longer or is something amiss? Thx.

dmanders

Just an update on this. The car is in for service to have this looked at. SA said he had never seen this warning before. Last I heard they are still trying to figure it out.

dmanders

Got the car back. Nothing seriously wrong. They had to let it sit at idle for a bit to warm it up and then drive it fifteen miles before the warning light went off. They said it didn't throw codes. They said this was a new warning system designed to be more informative than throwing a CEL.

retom

This is the first time I hear about such a warning in Q8 with petrol engine. Could you please write more about what this warning looked like and where in the owners manual you found the description of it.
Is this some new warning system in MY2021?

angrypengu

I think I've seen this in the manual of the A8. There's a sensor that measures fuel dilution, and there's also a TSB out that indicates 'oil level too high' as a result of cars not being driven long/hard enough combined with auto start stop that causes fuel to not be burnt off enough.

dmanders

I have a 2019 Q8. It is on page 233 of the manual. The warning appeared upon start of the engine in the usual place for warnings. It appeared as a yellow dipstick with the comment to drive the vehicle to warm it up.

Thanks angrypengu for the excellent explanation.

retom

This problem is well known in European Audi cars but affects cars with a TDI engine, mainly 4.0 TDI and to a lesser extent 3.0 TDI. It occurs in cars operated mainly on short distances, in which the DPF filter does not fully regenerate. Unburned fuel enters the engine oil, dilutes it, and a message appears that the engine oil level is too high. Yes, the problem is well known to Audi but as far as I know, still not fully resolved in TDI engines. Audi services usually suck off such excess oil, which in my opinion is not a good solution because the thinned oil loses its lubricating and preserving properties. There are several European forums where this problem is discussed and it is also mentioned in the manual of cars with TDI engines how to proceed in the event of a message about excess engine oil.
Interestingly, I did not know that the same problem occurs in cars from the US market with TFSI engines.

dmanders

Great information. Thanks!

Elementalism

I had this several times last winter. Mainly because i was driving it in MN winters 1.5 miles each way to the train. I drove on the highway for about 10 miles, parked it, and the warning went away. I don't take the train anymore into work and thus drive much longer lengths this winter and have not seen the warning yet.

imdakine1

Interesting I have a 2014 Q5 TDI and don’t drive that much not just because of COVID but I’ve had a virtual job since 2010. My co-working office in 2 miles away and all the grocery stores are probably within a mile or two. I’ve not seen this before... I’ll see if our manual says anything. I have had the check engine light in for a while before but it was due to a recall that was already known etc...Beyond the TDI scandal, the car is great and we intend to keep it for a long time and hopefully be sitting with a new Q8 in the near I future.