AudiAllTheWay

250,000KM and still running 👍

Recommend to try the piston soak and oils discussed here and please let us know how that goes for you. Your feedback would be appreciated!

AudiQ72017CREC

I know some with 420k km and still running... 😉 CREC is a rly nice engine but needs attenction (12 injectors [6 MPI], cast-iron cylinders, roots blower, etc.)

The oil issue is well known in PL and most of the ppl used to carbon clean and soak the pistons/rings (Engine Flushes IMHO are sh1ty).

kelisko

I wish I had this information before or even after purchasing my high mileage A7 with the CREC engine. I wouldn't have purchased it at all or if I did, a piston and valve soak would have been the first thing I did. That would probably have prevented my likely burnt exhaust valve(s) leading to zero compression and a misfiring engine that needs to be rebuilt. 😫

I also believe engine flushes are not the solution but I've been wrong before.

gbgastowers

The new piston rings (mostly oil ring) used in todays engines are designed to increase engine efficiency. These rings are also contributing to the oil consumption and carbon buildup problems we are experiencing

silver_tt

You are absolutely correct but there are other contributing factors like direct injection. Case in point: My 2002 Porsche 911 Turbo uses basically the exact same oil control rings (Nikasil requires low tension rings) and does not have oil consumption issues.

AudiAllTheWay

VW AEG 2.0L engine from late 1990’s to early 2000’s had sludge buildup issues in the piston oil rings causing burning oil in higher mileage engines. A piston soak was the solution back then and it works 👍

This is not a new issue.

dohturdima

Question is, is piston soak something that can be done as a preventative maintenance on an engine that (does not yet) burn out, or is it something that is done only when there is noticeable oil burn? How often does it need to be repeated?

kelisko

No oil consumption does not mean no carbon. It starts building up the first day you fire the engine. The more carbon gets deposited and the longer it is exposed to heat, the harder it is to clean up. With what we already know about this engine, I would be soaking pistons and valves every 50K miles since the issue seems to be occurring right past that mileage for some owners. This early preventive maintenance may also prevent the failure of the PCV.

ripping08

Had the same issue with our 2017 Audi Q7 and now the engine is close to blowing, and we've been told our only option is to replace it. A cylinder is misfiring and Audi is telling us the compression is low on one cylinder causing the need for an entire replacement. They don't know how long it will last. It's crazy. We've only had the car 4 years, purchasing in 2020, with only one other owner who also kept all of their service appointments like us. The oil consumption issues only started in the last year and every time we took it in we were just told everything was fine and the consumption issues happen sometimes with weather. We're so upset as we were only 2 years away from wrapping up payments and weren't expecting a faulty engine from a luxury German brand like Audi. I would say force your service center to address it. Look up the possible issues that have been mentioned in the forums. Make sure your fuel injection system stays clear, there are some other possible causes too that I've seen in the forums that you can catch ahead of time so you don't end up in a situation like us. Or just get rid of it as soon as you can. This is the worst experience I've had with any vehicle. I am very disappointed in Audi.

kelisko

@ripping08 Very sorry! Me and some others are in the same situation and understand your frustration. Can you remember the mileage your car reached before starting to consume oil? May you also please let us know the rate of your oil consumption right before the engine started choking? 1 quart per how many miles?