DirtyVegasTT

I always thought that when I got my S6 used with 13K miles it didn’t drive like the new ones I have driven in the past. In fact, it didn’t feel like the car drove like a 435 HP vehicle should. Maybe I was spoiled coming of a modified 500+ HP E55.

As time passed I have modified the S6 quite a bit, documented my progress with dyno and shared them on this forum. As my numbers went up and down depending on what software I used I still felt like there was something holding my car back.

https://www.audiworld.com/forums/sho...highlight=dyno

I heard about the carbon buildup issue, but never really have given it any serious thought. After all, this was nothing that concerned me, this only concerned those ‘other’ people, you know, the ones that live in the cold weather, that don’t ‘really’ drive their cars, and the ones that complain just about everything on this forum. I read about their horror stories when the VW engines were opened, or what the RS4 owners experienced with before and after dynos, but still thought that it didn’t pertain to me. This was not my problem I thought… but deep down inside I still could not explain the lackluster performance my V10 was exuding.

I convinced myself of just about every excuse I could think for my car’s mediocre performance. I thought of things such as powertrain parasitic losses or the fact that the V10 engine just runs too hot and pulls the timing. I made every excuse in the book for my V10 until finally I went back and started to read about the carbon buildup horror stories that plague the Audi family.

I talked to my service rep at Audi and told him that I thought the lack of power and speed I am experiencing may be due to this carbon buildup that no one at Audi wants to talk about. By the way, have any of you guys ever talked to Service reps about it? You get this dear in the headlights look from them and then they start telling you stories about nothing that pertains to the real problem. Well anyways, the answer I was given is that the only way that my car could be looked at for carbon buildup is if there is a code thrown by the ECU for misfires, and since I did not have a code thrown then I must not have the carbon buildup problem. I certainly didn’t really like this causal relationship I was told of, after all, it was possible that I had carbon buildup and my ECU was simply not throwing the code.

Well, a few months ago my car started to misfire. At first I didn’t think of it really, thought it was just the coilpack issue. The Audi service rep did such a good job convincing me that it wasn’t a carbon buildup that I never thought of it since. It wasn’t until the 4th day my car was at the service department that this topic came up again. I was told that my car continued to misfire and the top end needed to come off for cleaning. “Cleaning?” I asked, “But why?” Well, apparently my engine was all gunked up with enough carbon that it wouldn’t stop misfiring. The messed up part about it is that the code was not thrown by the ECU until I had carbon buildup that prevented normal engine function.

I wonder if this carbon buildup was responsible for my intake manifold that needed to be replaced a few months back due to one of the flaps inside that was not functioning properly. I heard of RS4 intake manifolds getting so junked up with carbon that the manifolds would fail. So if this was in fact the case for my intake and when my intake manifold was replaced the Service Department did not undertake the cleaning, even though it had to have been evident that my engine is just plagued with carbon. This is a perfect example of Audi’s attitude towards this issue.

Here is my engine with its top of. I think my rep was too afraid to give me a clear pic into one of those black holes to show me what was really going on in there at 49K miles.



After the car was cleaned all I could say is WOW. The car drove like it should have from the very start. I was beginning to think that this just can’t all be in my head and decided that I have to go back to the dyno and do some pulls and see exactly what was happening.

On the dyno I couldn’t get the 3rd gear pulls that I wanted because my stability control was coming on, but I was already making more power than I did before which was a good sign. I decided to put her into 4th gear and do pulls in 4th. The results astounded me. After decarbon cleaning my car gained 55HP and 25TQ to All Wheels! These are unbelievable numbers. The only thing that changed was that I added 20” wheels in-between the 2 dyno sessions, which should have reduced my performance if anything. I can’t imagine the numbers I could be making in 3rd if I could get the car to behave itself on the dyno. Also, the dyno run prior to this one was about 15K miles ago when my car showed no physical signs of any carbon buildup.



Sorry for this long rant but I thought it was necessary. I believe everyone should know about this as this issue affects EVERY Audi vehicle. Do not let ANYONE tell YOU otherwise. As you are driving, every day, little by little you are building up this black deposit in your engine that quietly robs your cars performance until one day you wake up and realize that your car just doesn’t drive like it used to. The F’d up part about this is that Audi knows this… everyone knows this, but no one talks about it and there is no fix for it other than cleaning the guts of your engine’s intake.

I hope people read this and I hope that it will make them mad enough to start to research this on their own and find out how much performance they have lost to this issue. I truly believe that more people have to put their cars on the dyno and see how their vehicles perform so that these things can be kept track of. If enough of us do this and make our voices heard, then maybe Audi will finally publically admit to this issue and will start working on some sort of solution for it and not tell its consumers how misinformed they are when this issue is brought up.

Until that time comes, get ready to cough up serious money for cleaning every 10K - 15K miles.

Here is some good additional information for research. Please read and educate yourself on this issue.

http://www.audizine.com/forum/showth...-up-Megathread

Here are some horrible pics of what is being discussed above. These are all pics from Audi engines, some of them with only around 20K miles:











AND FINALLY A VW GETTA GLI WITH SOME MILES ON HER:

MikeZ LI

wuold this fix be covered my the new car warantee assuming it hasn't expired?

DirtyVegasTT

Only if the car is throwing a code. Otherwise no. So you're basically screwed until it gunks up your engine to the point that it is so dirty that the car misfires and internal engine components do not function as they should.

One thing I forgot to mention is that some people I know in the Audi service say the the onset of carbon buildup happens as early as 10K miles. That is really scary! It basically means that decarbon cleanup should be a part of your 10K maintenance. I plan on having it done every 15K miles or so going forward.

chuckee98

Is the first picture of yours? Did you take any more? Yours covered under warranty? If not, any idea of cost? I shudder at the thought of the headache involved with manual cleaning every 15k miles. (Though that would be about every three years for me.) At my second annual oil change just under 10k miles, I had them do the BG chemical clean as a preventative measure to the carbon buildup. I plan on doing that every year just prior to an oil change, which would be every 5k miles. It's nowhere as effective nor as complete as a full top end tear down and cleaning, but maybe, just maybe, it'll slow it down a bit. (Sure, with my luck, just enough to throw codes AFTER the warranty runs out.)

Thanks for the info.

DirtyVegasTT

The picture with an engine block open is mine. It wasn't me who took it, it was my service advisor. You certainly don't have to clean it every 10 or 15K miles, but if you don't that crap will just grow inside your engine draining it of proper airflow and power. I heard that some motors even have certain parts cease if enough build up occurs. RS4 guys have it really bad and have it documented, but it seems like all VW/Audi motors fall prey to this garbage.

MikeZ LI

Cost for this service please.

gkb

Wow I don't even want to know what mine looks like, can this also affect Gas mileage? I say we start a campaign. We all open our hoods, hold up a sign saying "Customer Satisfaction....Carbon Buildup? We Know!" take a picture and send them to Audi of America.

DirtyVegasTT

Depends who is doing it. If its a dealer that you have no connection with I would think it will be around $1,500 or more to start.

mariof

THANK YOU for this thread and the information. I always thought the same thing about my 2007 S6: it feels underpowered for a car with a 435hp V10. I bought the car in January with 21,000 miles. While it certainly has plenty of power, I expected more. Last night, while driving home from work, I felt a little hiccup as I was getting on the parkway and the CEL came on.

I ahve an appointment with the dealer for next Friday. I most certainly raise carbon buildup as a possible culprit when I chat with the service manager.

Mario

john_S6

I had the same problem at 55k miles, the car sat in the dealer for a week. I was told carbon buildup is common on 3.2 but very uncommon on v10. But after reading all of the forums the problem is common everywhere some versions more than others. Once I received the car back and notice the big difference on the power band, I took some necessary steps to install catch can and meth injection to avoid the same problem. Before everybody starts yelling, it was my decision to install catch can and meth to help fight the problem. I only have the system for about three months and so far the car pulls like an animal all the time without any hesitation. Waiting on another month or so to change the oil and empty the catch can and see the results. I not saying the catch can and meth is the solution, but it should help fight the problem.