vulcan46@earthlink.net

I have a 2014 A8 with the 4.0T engine. At 30K miles the EPC light came on. Took it to the dealer who found that cyl #3 had a fouled plug. They said at the time that the spark plug was loose. Sounded improbable to me. They serviced the car and changed all the plugs. 3K miles later the low oil light came on. Took it to the dealer who said it was normal for Audi's to burn oil even though this was the first time the light came on. 5K miles later (38K total miles now) the EPC light came on again. The Audi dealer found cyl #3 and #6 with fouled plugs. Their diagnosis was that the plugs were fouling because I wasn't always using top tier fuel (i.e. fuel that has detergent additives - I always burned 91+ octane). They gave me a list of brands to buy from. 3K miles later I took the car to an independent mechanic to inspect the plugs. The mechanic reported oil fouling on #3 and #1 plugs (the only ones he pulled). Took it back to Audi who told me that some oil on the plugs was normal and that there was nothing wrong (I had to pay the dealer out of pocket to inspect the plugs because they claimed no problems with the car). Does all of this sound normal and expected for this vehicle?

RED HORSE

Were it me, I would first talk to the GM (I did that this morning at my dealership) and express my concerns. If you don't get a satisfactory my second step would be try another Audi dealer if there is one reasonably close. Third step is try to contact Audi. Last effort is to use the dealer's FB page to publicly express your concerns.

My S8 burns some oil, but not sufficient I need to add between scheduled oil changes.

vulcan46@earthlink.net

Thanks for your comment. I've given up on this dealer. After basically telling me that buying the wrong brand of gas was causing my plug fouling problem I lost all confidence in them. I called a different Audi dealer and talked to the service shop foreman. Told him my problem and history and he laughed at the "wrong brand of gas" explanation. Unfortunately it is an 80 mile drive to this new dealer but it will be worth it if they can actually diagnose and fix the issue.

MP4.2+6.0

1. Do you drive the car longer distances commonly, or lots of short trips where it may not really warm up?
2. Was any work ever done on fine oil separator/PCV related system?

vulcan46@earthlink.net

My driving is typically 70% freeway and 30% in town. I do mixed driving (short and long) but most trips are ~10 - 20 miles. I have taken 80+ mile trips about 10% of the time. Never had any work done except standard maintenance (oil,etc.).

LexusLSguy

The fact that it's happening consistently on the same cylinders most likely means your piston rings are not sealing against the cylinder walls very good. This would lead to lower compression in these cylinders as well. Oil seeps through into the combustion chamber. A compression test would verify this. You are burning a good amount of oil which is causing the fouling and it is not normal. Yes, all engines consume oil but yours is drinking too much. Audi is giving you the run around as they I am sure don't want to replace / rebuild the engine if necessary. Hopefully it's not this serious but I would do a compression test to verify. Ask cooperate for help too if you are not getting anywhere with a service manager. ​​

The oem oil change interval is too long for these engines too. Turbo / high compression engines are really hard on oil as well. You could also try an engine flush (recommend Liqui Moly product) to see if this helps. It has been known to reduce consumption but it depends on where the consumption is coming from.

vulcan46@earthlink.net

Thanks for the feedback. This vehicle is in warranty and fouling plugs. It irks me that the dealer won't own up to the issue, troubleshoot, and do the repair. Not sure why since I believe that dealers are paid for warranty repairs from Audi. I can only guess that this particular service department is incompetent. It will be interesting to hear what the second dealer says when I bring it in next week. On the phone, they seemed to understand that there was an issue that needed repair. I really don't want to take steps to temporarily mitigate the issue only to be faced with a $10K repair after the warranty expires.

MP4.2+6.0

From your prior reply, I would ask them to look at the PCV/fine oil separator. If that is not working properly it could pull extra oil into the motor. There are a fair number of reports of failures there on the board if you poke some. Many are noise based complaints, but it can also pull oil into the intake by its very nature if malfunctioning.

In contrast to one of the replies, I don't think you have stated the amount of oil being burned. If you know that (or I missed it), report it to dealer. If not, start tracking carefully. If you have just the display to go by (no dipstick), have it on a known mark and then get some observations from there. Audi can be looking for a quart per thousand IIRC, which itself is kind of an absurd burn rate. Mine uses essentially none between service intervals and my D3 W12 the same, even at 100K+. But in any case, you would want to be reporting both oil burning and the plug fouling issues backed up by data if those are both true. And yes, it could be internal engine too but then that really isn't something the V8's in general are known for, across a lot of years now.

vulcan46@earthlink.net

Thanks. That's great feedback on the PCV/fine oil separator. I will mention that to the second Audi dealer that I will be visiting for service next week. I have not actually tracked oil consumption yet but noted that 3K miles after an oil change my low oil indicator light came on. That is the first and only time that the indicator light came on but it was suspicious that it happened at the same time that the fouling started. Audi claimed that this was normal oil consumption even though the vehicle only had 30K miles on it at the time.

Stevereddy

They need to figure WHY those plugs in particular are fouling. Cool problem or is it a piston ring issue? A leakdown test and compression test should be performed along with PCV diagnostic. Hopefully you are under CPO in case this is a serious issue. Please let us all know what it all comes down to. I have a 2014 A7 4,0 with 16,800 miles on it, all great so far