Audi A5 2.0 TFSI 2014 - Oil condition at 3k miles

[stevealmond63]

First service at my local mechanic after 4 years of servicing from new by Audi dealership and the mechanic tells me he’s surprised by the condition of the oil that he drained.
The car was booked in for a full service with Audi 12 months ago but has done only 3k miles since. The mechanic showed me the oil he’d just drained which was very dark and thick...almost treacle like.
I’ve queried this with the Audi dealership and they tell me it’s normal. They say the oil draws in moisture from condensation in the engine because (in low mileage cars) it never gets up to temperature.
Just looking for advice - if anyone can confirm that what the Audi dealership is telling me is correct. Many thanks!

[GreenV8S]

It's true that water accumulates in the crank case when the engine is cold. In my experience this leads to emulsion (usually accumulating in the coldest places such as under the rocker covers) rather than thickened oil, but perhaps you're using some special oil that behaves differently.

[tapkaJohnD]

"TFSI" indicates Turbo Fuel Stratified Injection. This the modern technology that injects petrol into the chamber, as does a diesel, in a way that allows a very lean mixture in most of the volume, but rich, or stoikiometric, mixture at the spark plug to promote ignition - a 'stratified' charge. This is under electronic control from the ECU, that will only produce this stratification once the engine is warm and running at a constant speed. Low milage and short trips never attains this, and the engine persistently runs rich. All engines suffer 'blow-by', piston rings never work perfectly, and you are seeing the result, excess carbon and probably petrol in the oil.
Increase your mileage, take longer trips or, if you only require a car for short trips, invest in an electric one!
John

[thebraketester]

Mine turns the oil black almost straight away. I wouldn’t worry about it. I would worry more about excessive oil usage.

Edited by thebraketester on Wednesday 13th November 19:15

[xjay1337]

Send it for an oil analysis

[stevealmond63]

tapkaJohnD said:

"TFSI" indicates Turbo Fuel Stratified Injection. This the modern technology that injects petrol into the chamber, as does a diesel, in a way that allows a very lean mixture in most of the volume, but rich, or stoikiometric, mixture at the spark plug to promote ignition - a 'stratified' charge. This is under electronic control from the ECU, that will only produce this stratification once the engine is warm and running at a constant speed. Low milage and short trips never attains this, and the engine persistently runs rich. All engines suffer 'blow-by', piston rings never work perfectly, and you are seeing the result, excess carbon and probably petrol in the oil.
Increase your mileage, take longer trips or, if you only require a car for short trips, invest in an electric one!
John

Many thanks for the detailed reply John. I had to Google stoichiometry!

Rather than invest in an electric car I think I'll change the oil more regularly - but thanks for the suggestion ;-)

You've put my mind at rest and I've now explained to the Audi dealership what they couldn't explain to me! I'll also let my mechanic know.

Cheers!

[mercedeslimos]

To be honest, that would be a thousand miles away from a normal change for me anyway. Plus, the TFSI loves a drink of oil too, and a between a litre and two would have been topped up in the 5k between services. Oil is cheap, much better to shorten intervals than try to push it out and risk engine wear.

[xjay1337]

mercedeslimos said:

To be honest, that would be a thousand miles away from a normal change for me anyway. Plus, the TFSI loves a drink of oil too, and a between a litre and two would have been topped up in the 5k between services. Oil is cheap, much better to shorten intervals than try to push it out and risk engine wear.

Maybe fked ones.

Good ones use little to no oil.

There was a recall for these.

[mercedeslimos]

xjay1337 said:

Maybe fked ones.

Good ones use little to no oil.

There was a recall for these.

Any idea what the recall was?

Mine used to take 1/2L in 1000 miles, then I fitted a Forge PCV delete kit and that cut down consumption to about 50ml/1000miles. Thought I've also heard that the factory PCV is better.