2012 Audi Q5 2.0T PP - Mystery Oil Consumption

[rguirguis]

Hello All,

This is my first post so apologies in advance for what may seem like a repetative post. I recently bought a 2012 Audi Q5 2.0t with 158000 miles and no real documented history other than a car fax. Given the price I bought it for, I suspected there was some hidden issue with the car as it seemed in too good condition cosmetically and mechanically. After only driving 200-300 miles, I noticed it needed a quart of oil. The oil was due so I changed the oil and filter and found that it still burned oil at the same rate. I read extensively about the 2009-2011 models having the piston ring issue. I am way out of warranty and AoA told me to pound sand due to high miles and no prior relationship.

The dealer recommended an oil consumption test, which I agreed to, but they refused to accept the results when I returned as I removed the oil cap once to check vacuum during idle, which created single instance fault codes. Thinking it could be an easy fix, I also changed the oil separator with a new OEM one The dealer also rejected it, claiming that it ruined the test. The dealer wants me to run it again, but I am not sure confirming this with them is going to provide me with any outcome other than a lighter wallet (Yes, they are charging me due to high miles). Given the other issues they have seen in the past, they are jumping to the default response that it is likely the piston rings (which I would have to pay $6000 out of pocket for), but I am not convinced as there is no way they could have done a deep dive on the car during their 90min non-invasive diagnostic session on an unfamiliar car. While they tell me its process of elimination, I am not convinced they really eliminated other consumption culprits during this short time.

For those that are interested, the car does not visually leak oil anywhere above, below or on the engine but I did find the plugs were pretty fouled up for only having 6K on them. I sanded them down and re-installed but I plan to replace them in the morning to see if it happens to the new plugs too. There is no check engine light. I have yet to do a compression test (also tomorrow), however the car runs very smoothly, accelerates very well, idles smooth and does not put out any blue smoke (per the opinions of several mechanically inclined people). There is even a strong vacuum behind the oil cap which does cause it to idle rough when removed (I was told by the dealer this is normal and actually good). There is a normal amount of dry soot on the exhaust, no spatter on the rear bumper and it does not smoke on startup. It does give a small puff of BLACK smoke on revs and does smell of fuel, even after a few minutes. One person said it could be running rich and perhaps the turbo is not supplying enough air/boost for high revs (~4000 rpm). They think it may even leaking oil into the intake or exhaust line, but I have yet to diagnose the spool for play or oil in the inter cooler. I have read that others have reported valve seal issues, especially on startup, but I am not sure I am confident enough to check this without doing further damage.

Maybe I am in denial, but I would expect some noticable performance symptoms if it indeed were the piston rings. Given the car made it this far without major repair per CarFax, I am having a hard time accepting piston rings as cause until I give other potential causes a good look over. This is by far the most bizarre car issue I have ever experienced because there is nothing I can find wrong with this car other than excessive oil consumption. Even my car friends are stumped. I am setting some time aside tomorrow to check all these potential issues as best as I can. I just want to find an obvious cause, but am not optimistic I will find one.

Before I cave and consider pursuing the expensive piston ring replacement fix, I wanted to ask if anyone else with a post-2011 2.0t engine had any luck resolving this matter with a fix OTHER than the piston ring replacement? How many people have actually had to do ring replacements on 2012 and newer? Did it actually fix your issue or did it return later? Are there other issues I should be looking for when I check it out? I am new to the brand and am still learning this engine.

I love driving this car and hate the thought of having to sell it so soon after buying. Thanks in advance for ANY insight.

[bakedziti]

The B8 A4 guys generally would suggest you replace your engine with one from a recycler for about $2,500. All the 2.0Ts should work for your car from 2009-16; clearly we go for 13 and high engines with the lowest miles. My engine was replaced after losing a rod bearing 24k miles after Audi completed Stage II of my oil consumption, I’ve been so much happier since just replacing it.

[Mythdoc]

Tens of thousands of vehicles before you have exhibited these symptoms and been fixed by new piston rings. You are indeed in denial, or at least in need of a refresher in Occam’s Razor. On the other hand, whoever sold you the vehicle should have disclosed the condition. It didn’t just start happening. Gradually, that car has been needing a quart of oil at shorter and shorter intervals.

Moral of story: check forums before buying any older model car.

[rguirguis]

Hi All, thanks for the reply. I know I am in denial, but perhaps the engineer in me wants to see if I can find an alternative fix. I did take off the air intake on the turbo to visually inspect and all seemed well. I also removed the O2 sensor between the turbo and cat and inserted a camera to view the turbine. Again, it seems well. I even performed a compression test and was getting 190 psi on all 4 cylinders.

I dont doubt now that the oil control ring is one cause. I just worry that I will have to spend thousands more if there is another issue to fix (it seems to run rich too). I cant imagine the oil ring being broken, but I can see it being carboned up to the point its not scraping the wall. Per camera, the pistons as well as the new plugs I put in 200 miles ago are now already black. Same with the O2 sensor that I pulled today again. Before considering a rebuild, which could create more problems than solve, has anyone had any luck with any interesting tricks to narrow down or help resolve?

For example, I tried adding an ounce of Marvel Mystery Oil, directly into cylinders 1 and 3 to soak for a few hours. The idea was to help release any junk caught up in the oil ring that is causing it to not scrape the wall or allow oil through. It smoked like crazy for a few minutes after starting it up, but the engine eventually went back to is normal BLACK smoke on rev and continued to lose oil. I almost forgot to mention that the oil that I now only has 500 miles and is already black. Not sure if its burnt or is just now full of loose carbon deposits.

Thoughts?