2011 2.0T Q5 - hi it's me, high oil consumption

[turmoil]

Single owner Q5 here. I've never had oil consumption issues with this car in the past 10 years. I'm sitting at 114,500 miles right now, brand new timing chain.

Within the past 3 months i've noticed that i've been going through about a quart of oil every ~500 miles or so.

I just had the timing chain done by a local indie shop back in March of this year when it was sitting at 111,200 miles. I started noticing the consumption around 113k.

Is it possible that something during that installation could've been installed wrong and may be causing a leak? I'm not seeing anything, so not banking on this being the issue, but just curious if it could be related.

Over the course of its life I had the dealer check for high oil consumption (back in 2013) they replaced the pressure regulating valve (25k miles).
Later in 2016 there was a recall on the Crankcase Pressure Regulating Valve (PCV?) and they replaced mine at 75k miles.
I've read that a clogged PCV can cause oil consumption issues, and mine was last done almost 40k miles ago. Time for a new one certainly, but could that be the issue?

The only other issue is i've had a CEL for P0299, turbo underboost. This has been going on for some time, but intermittently. Is it possible the turbo is failing and if so, would that cause high oil consumption?

Or are the piston most likely the culprit?

I was hoping to hang on to this car for a few more years if I could avoid major bills (pistons, transmission, etc), but maybe it's time to say goodbye. What do you think?

[S4'ed]

Assuming oil is not leaking from a gasket, and dripping on the ground.....it is either the PCV/Pressure regulator unit ($150), or the turbo bearing/oil-seal is bad ($1200), or the piston oil-control rings are clogged ($6000).

[turmoil]

Yeah I’m not seeing anything leaking so likely one of the 3 you mentioned.
I’ve only ever had a CEL related to the turbo so I’m inclined to think that could be the culprit.

Going to have my local shop take a look and see if they can diagnose further. Thank you!

[turmoil]

Small update. Took it into the shop and they couldn't find anything that was a definite culprit, but I had them swap out the PCV because mine has had over 40k miles on it and I wanted to at least rule that out.
When the mechanic removed it, he said there was a ton of oil that came out (like a 1/4 of QT) when there should be none. So, maybe that could've been the issue? I'll drive it for a bit and see where it's at.

[Discipulus]

Hope that fixes it! PCVs are notoriously failure prone. Crossing my fingers for ya, as the other options aren't fun.

Sent from my SM-G988U1 using Audizine Forum mobile app

[turmoil]

Hope that fixes it! PCVs are notoriously failure prone. Crossing my fingers for ya, as the other options aren't fun.

Sent from my SM-G988U1 using Audizine Forum mobile app

Me too :)

When I was driving over to the shop before i had it replaced my wife was following me in her car and said she noticed some dark smoke come out of the exhaust when I would accelerate from stopped. Not sure what exactly would cause that.

[turmoil]

Time for my yearly update.

Sitting at 121k miles. I'm averaging about 1,000 miles to a QT since I started really documenting it the past year or so.
I'm not seeing anything leaking oil. I had one recurring CEL come on (P0299 turbo underboost) but haven't seen it for ~6 months.
Lately the low oil warning seems to come on more and more frequently, feels like my miles to a quart is getting down to like the 6-700 range (below my 1k average).

Thinking about having my shop take another look at it.
Is there a way to test to see if it could be clogged piston rings or any other indicators for that?
I've only ever had CEL related to the turbo charger, so i'm inclined to think that could but the culprit? My chrome exhaust tips seem quite dark and every now and then you can see smoke from the exhaust, but not all the time.

[StuckAntichris]

Unfortunately there is not really a good way to "test" the rings for oil consumption. Not only is there a new ring design but the pistons themselves have been updated. The original pistons actually have a cutout in the bottom of the oil ring shelf. This cutout was for getting the wristpin installed. The new pistons do not have this cutout. Ill try and get a picture of what I am talking about when I get home today. How often are you changing your oil? Reduced oil change intervals have seemed to help with timing chain stretch and preventing/prolonging oil consumption.

That being said changing your oil more often will not fix your consumption issues once they start. I hate to be negative but it looks like your options are piston replacement or keep adding oil every 600-1000 miles

And last thing, for the 2.0T engine the A4 forum has much more traffic and a ton of information on options for this issue. LINK

[turmoil]

Thanks for the link! I'll take a look around the A4 forum.

This has been a car I drive a few days every couple of weeks for the past few years, so oil changes are usually around 10 months or so, which has been ~3-4k miles give or take. So it has definitely been sitting idle more often than not.

[StuckAntichris]

20221220_180101.jpg20221220_180041.jpg

Here are pictures of original vs updated pistons. Look specifically at the edge where those cutouts are. My theory is that once the oil wipe rings clog up the oil sprayers in the bottom of the block essentially are spraying oil behind the wipe rings allowing for more to be consumed. No real proof of that theory but they updated the pistons for a reason right?

[S4'ed]

I don't think the oil sprayers are a contributor to the oil consumption issue, they spray the underside recess of the piston, they won't get much, if any, oil between the side of the piston (near the wristpin) and the cylinder wall (where the oil return cut-outs are).