cue

UPDATE:

During an oil consumption test dealer calculated .1 Quart/1000 miles. Something still does not add up?? I added 1 quart in 5000 miles? Unless it was .5 quart low when we got it, plus the .5 it used in 5000 miles?

AUJ

Audi FSI motors burn oil secondary to the oil's repatriation into the intake via the PVC and emission system. It later turns into carbon in the intake and melts onto the valves resulting in a loss of power and loss of ignition completely in direct injection motors. It is best documented on the RS4 variant and is easily studied. There is a TSB on how to clear the carbon. Perhaps have them check the oil feedback loop via the emissions system. I have an FSI as well, but the benefit outweighs risk, imho.

http://www.youtube.com/watch?v=n7I4OAQHm7c

AUJ

Found out a little more about the FSI carbon issue from an Audi source. The oil catch cans people are installing on the RS4 variants does not prevent the issue. Apparently, the modified fuel injection process combined with cr@ppy gasoline, particularly in the U.S., causes the build up issue. Supposedly, the German team was a bit baffled by the outcome. They have a different fuel mix standard in the Fatherland which does not produce the carbon issue. However, in U.S. specific vehicles there is a TSB that entails pulling the intake manifold and sand blasting the valves with a specific material to get the carbon build up off. The blast out the intake as well and performance is restored. Not that bad really.

Posted this on 09-22-2002 when RS4 stuff was just rumors flying in tight circles.

https://www.audiworld.com/forums/sho....php?t=2535669

Was later shouted down by the same tourist K.A. that takes people to The Ring and fancies himself connected. Forgot his name. Doesn't matter because it turns out the American gasoline caused greater problems on the new designed motors at that time.

Anyway, AG engineering never got all the bugs out and only figured it out from someone remembering the other high sulphur gasoline issues. Only bringing it up so as to figure out if all the many blends complying with different State's fuel mix standards can be targeted as specific culprits. Maybe there can be a compensatory additive that can reduce the carbon build up risk to that of German FSI's.

Have owned other 4.2s from Audi including old S8; this FSI variant is my favorite and it is really fun to shock people as to how fast it can move the behemoth Q7. It moves the Q7 a bit better down low than the 4.5 in my Cayenne S moves its platform. Kind of a pisser. This post is not an open challenge. Let's use our collective heads to help identify the chemical mix in U.S. gas spoiling the FSI fun for some. Hope this information helps.

Another good thread about fuel dilution from a non-competing forum with pics.

http://www.bobistheoilguy.com/forums...Number=1325647

AUJ

Talked to another source today. Currently, there is a lot of 2.0T pistons being replaced during the production run times of your vehicle. Apparently, the supplier made the piston diameter a hair less than spec resulting in increased oil consumption secondary to blow by. I am not trying to panic you, but any Audi tech here will attest to doing the piston change out on 2.0s secondary to this condition. Hope information provided here helps solve the issue. Mostly, I hope the piston supply fault issue is relegated to only the 2.0. Only stand out 3.0 issue I hear about was the coolant pump relay plastic housing or something causing failures. Replacement parts with new metal housings have been implemented.

iconoclast

2.0t?

AUJ

On the A4s, Q5s, A6s et al; was speculating that the piston suppliers utilized by AG sourcing for the same period my cross over to other Audi engine block supplied internal parts as a possibility.

iconoclast

i was confused, i thought it was either a typo and you meant 3.0t or you were under the impression that Q7s came with 2.0t.

AUJ

I wonder if the pistons are sourced from the same OEM supplier on the 3.0T. Got a separate confirmation that the pistons on the 2.0s were just off spec enough to cause unacceptable oil consumption. I believe the supplier will be getting the bill for the collective tech's hard work to change to the pistons. My friend in a Cali dealer has done 5 2.0T A4s under factory directive just by himself so far.

cue

Update to my oil consumption: After meticulously documenting the oil consumption over the past year, and staying in constant contact with my service manager, I think the issue is solved. (Hope I did not jinx myself.)

The dealer did an oil consumption test in September of 2011, which showed .1Q/1000 miles. (I think they performed the test incorrectly, but that's a story for another day) Over the next year, my actual results averaged .65Q/1000 mi. (Yes - you are reading right, I added seven quarts of oil between the 15K and 25K Service!) Just did not add up - hence my persistence. This past summer, the service manager told me about a TSB that was coming out on the 3.0 (similar to what was done on the 2.0's) for oil consumption - it involves a crankcase breather hose and re-flash of the ECU. They performed it about 2 months ago, and after about 4000 miles, no oil has been added. I've been checking the dipstick about every two weeks, and am happy to say it's still full.

See below for a section from the service report