porttac

Wilsonville.

porttac

https://audiclubna.org/north-atlanti...ld-up-removal/

Woodsie0520

Oil can touch the back of the valves through the PCV system. Occasionally you will have oil vapours that will come from the crank case and get vented back in through the intake that can contribute to the carbon build up on the back of the valves. This is why catch cans were created, to allow the crank case to still get vented from the pressures, but also uses baffling to try and catch as much of that oil residue as possible so that it doesn't make its way back into the intake stream.

toothandnail

seeing how the carbon build up is from the crankcase ventilation , that is oil evaporating and sucked out of the crankcase and drawn into the manifold and engine a good detergent gasoline will not help because

the gasoline will never touch the valves in a direct injection engine. a good oil that has low thermal breakdown can help along with a catch can. and of coarse adding some kind of port injection to wash the carbon off the valves would help too.

SchwarzS6

A catch can probably will not do much with these engines because Audi already has a pretty sophisticated oil separator in the PCV system.

cuke2u

Correct, plus my engine has two injectors, one to clean the valves with as far as I understand...

vkamnyev

My previous car was a Mazda 3 Skyactiv with direct injection motor. Owned since it was new and sold it after 6 year with almost 90k miles. It still ran strong with no signs of power loss or anything. Honestly I never even thought about carbon build up on that car. This is my first Audi... Is Audi direct injection inclined to produce more carbon build up than other DI motors? Also, is there an easy way to check if I have build up or the only way to find out is to take the manifold off and look with a camera? My A4 is at 30k miles now and I’ve used shell gasoline for probably 25k miles of its life.

hipendicular

We also had a Mazda with skyactive DI 2.4L engine (2013 Mazda 6). My wife drove it till it had around 140K of miles and zero carbon build up problems. I changed her oil every 5K with (semi crappy Mobil 1 from walmart) and I would beat on it when II would drive it as I know she was very easy with the gas (but not the brakes).. =( . I saw plenty of people complaining about carbon build up on this motor too.

So fingers crossed on both of our Audis. I'm currently at 40K and so far the car runs like new. I do one oil change between the Audi care intervals (5K). I beat on my car every now and then as hot oil is good cause it burns out the water and fuel, maybe pull in some of that carbon and its just fun to use the quattro and turbo.

Acuransx

My 2 cents -- My A6 (/15 3.0T) has 44K miles and no signs yet of any issues. FWIW, the service manager at my dealer (they have been terrific) told me that they don't see this issue too much on the A6 V6 but when it manifests itself it is usually north of 90K miles. He said that Audi has a procedure for this and told me I'd be looking at a bit under $1,000 -- not thrilled about this possibility but also should I keep the car long term (which as of now I do not intend to do) it will not be end of world.

Agree 100% with the intermediate (5K mile) oil change interval. Won't hurt anything and may possibly help. As for cuke's post would have been nice if VAG had the additional port injector like the European cars -- I believe that Lexus does it this way which washes the back of the valves in gasoline thus preventing the dreaded carbon buildup.

I spent too much time worrying about this already. My wife's A4 Quattro (/18) is leased so no need to worry about that one. As for the A6 should I decide to keep it past 65K miles I'll just have to see what happens. If I keep it and get to 85-90K miles without having to deal with the issue that will be great and at that time I will bid it adieu. Not going to spend any more time worrying about this -- just going to drive and enjoy.

Best,
Jeff

dbias

Just turned 70k miles and no signs of any problems. I try to buy low NOACK oil, under 8 percent. Maybe it helps, maybe it doesn't but with less evaporation I dont think it hurts