Right. I wonder if they still have a drain-to-sump PVC routing. I haven't looked at schematics for really late model dipstickless BMW's. Good point though.

The ad didn't say what the method was. It said their are pamphlets that provide more details but the dealership didn't seem to have them.

So do VW and Audi, and it does not stop the valve deposits. We see deposits at only 2k, 5k, and pretty bad by 25k on some cars. 50k seems to be the point where a lot of people feel they really have to remove the intake manifold and clean things up. Here is audi's triple-cyclonic oil separator via Rl_RS4. It is my understanding that for the photos of valve deposits at 2k I posted above, that car had this oil separator.

Also I wanted to pass along a quote from someone who works at a BMW dealership and has been tracking VW/AUDI/BMW deposits FWIW:

"BMW is having big problems with the 335, 135, 760 DI engines as well. I was talking with a BMW high up rep the other day and he went on to say..................."even the BMW induction chemicals misted pre TB will do little to nothing when DI motors have 50K". They are pulling intake manifolds and scrubbing until blue in the face. He also went on to say bmw is going to start suggesting 15K induction services from new on all DI cars."

To me, this reinforces what I have been saying above, unless you have a permanent fix where pcv gunk cannot get back into the intake tract at all (an inline catch can IS NOT a permanent fix), then it is important to start a preventative regimen as early as possible (see above list for items that can be done).

I think he is barking up the wrong tree by especially singling out negatives of MG detergents because those negatives are not unique to them.

This thread has a dual focus which is justified, IMO. The focus started on internal-to-engine varnish but intake deposits are equally worth discussing.
I found a very interesting link discussing Audi DI engine deposit issues. I am going to see how to take advantage of its recommendations.
http://vehicleserviceprofits.com/Documents/Audi%20Report.ppt

JAG, I need to read the rest of that presentation but the first slide is composed of only incorrect assumptions, or what they call "facts". These are not facts and they are also incorrect:

"Audi direct injected engine deposits overview of facts:

Audi valve deposit issues are predominantly in Northern winter areas like Illinois"

I disagree with this. The reported problems do not support this.

"Within Illinois, the problems are more pronounced in urban market than in rural market indicating potential differences in fuel (Chicago receives EPA mandated seasonal gas), or in driving patterns"

Really?

"Opinion of area Audi technicians indicates that the problems seem more pronounced with customers that drive fewer miles (rarely driven at highway speeds)"

This is not supported at ALL by the evidence!

"Many valve deposits are not hardened carbon deposits, but more typically softer deposits consistent with oil finding its way into the intake"

This is incorrect. Tons of experiences with people cleaning these. Why does a person have to use a walnut gun if it is soft. They have to soak the deposits for a long time in GM top clean just to have a chance at getting them off.

I'm not trying to be negative and appreciate seeing any info. on this subject, but those assumptions are wrong.

Saaber1,

In your experience does venting the PCV system to the atmosphere set any DTCs?

I don't know of any BMW systems running atmospheric so you'd have to look at the individual setup and/or try it to see if it would. I don't watch the BMW boards closely however so their may well be some out there.

For the VW/Audi 2.0 FSI engine, there are many cars running the bypass to exhaust setup, "race" catch can (which is a catch can that vents to the atmosphere instead of returning to the intake), and a few running a simple tube to atmosphere (what I've been calling "down tube" or "road tube"). No reported DTCs on any of these cars that I am aware of. The only negatives I have heard of are:

1) For race can, nasty smell (that particular can vents the gases into the engine compartment and they therefore can get sucked into the cabin). Note that "down tube" that exits beneath the car shouldn't have this issue.

2) One person who was running a Mann/Provent catch can and venting to the atmosphere reported a drop in low end power. I don't know if it was due to his particular setup, but it is worth noting and watching for in other setups. That is the only instance of this that I have heard of.

My philosophy has been to mimic the stock system as closely as possible (which includes maintaining vacuum pull of crankcase gases) and just have the pcv gunk going somewhere other than to the intake. Some possible ways to do this would be to route to exhaust (I like that because it is simple http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1463475#Post1463475) or an electric vacuum pump and dumping to atmosphere.

I have about 2800 miles on the setup which dumps pcv gunk into the exhaust. Normally by around 1500 miles after "seafoaming" I start to feel a little rough idle and have "stumbling starts". These are common symptoms for the 2.0 FSI and left untreated they get worse and worse until you have misfiring/loss of coil packs etc.

For example here are the valves of a car with factory recommended maintenance and good oil at 100k (not my car). Note that this car had mostly all highway miles (contrast to presentation above which incorrectly states that car with highway miles have less deposits, also note that vw patent says high rpms and light loads produce the most pcv glop)



Since the bypass to exhaust, I have had zero stumbling starts and idle has been smooth as silk. It also appears that the bypass is having no negative effect on oil but that is based on only one post-bypass UOA. Re: DTCs, note that crankcase gases enter exhaust post-cat and post 02 sensor.




For fun also check out this video of this beautifully clean BMW direct injection spraying in the cylinder. What a precise spray that is and imagine the effects on the car's performance if 50k worth of PCV goo is dumped in there over time.

http://www.youtube.com/watch?v=HHqrP18GCL4

Thank you JAG and saaber for the information and discussion in this thread. Ive been following since you started up. My Speed6 DI now has almost 24K, thankfully with NO reduction in fuel economy or performance. I am mistified by this and can only attribute my fortune to my commute being mostly highway at speeds in excess of 60 mph for at least 30 minutes, usually 40-60. Either that or Im the MZR doesnt notice the impact of the design flaw until later in life. My wear metals, for what the UOA is worth to detect wear, have been lower than most as well. Im starting to think that this issue will not be resolved with oil and intake cleanings alone, but an out of warranty modification such as the venting to atmoshere or a recall to install a beefier pcv system.

I would also like to thank JAG and saaber for the great discussion in this thread. We just placed an order for a 2010 750Li with the new twin turbo DI V8 and I'm worried that this engine will have the same issues. I'm wondering what I can do to help with the deposits while the car is under the dealership maintenance program. They probably won't allow me to use my own oil, and I don't want to play with the PCV system while the engine is under warranty. Would using Redline in between the dealership scheduled oil changes help at all? (draining the BMW oil half way through the interval?)

I think the deposit issue cannot be readily fixed with oil choice. I believe oil choice may help the problem but won't solve it. F.e. Mobil 1 0W40 I think is generally recognized as being good at deposit control. The above 100k photo was a car that used M1 0W40 every 10k miles.

As part of a battery of measures to combat deposits, using a low volatility oil and good cleaning oil makes sense I think. Do properties of ester-containing oils such as redline and biosyn make a difference? That is the question and hard to answer I think. Some things to think about:

In Rl_RS4's work, he thinks that Renewable lubricants Biosyn helps with deposit formation due to low volatility and cleaning ability. I haven't researched it enough to know this is true but he has put a tremendous amount of work into the issue and I would encourage anyone to track down his work on audi RS4 engines. I would love to see some solid before and after comparisons of Biosyn deposits vs other oil deposits.

I find this CRODA slide interesting as valves get tremendously hot (as much as 380C in the 2.0 FSI).



If the above indicator is true, it does make one think that oil choice may influence deposits. VW's patent seems to indicate that they rely on typical driving habits to "burn off" the valve deposits. But wouldn't the high temps actually increase the type of deposits shown in the CRODA slide? That is why I say the overall question is hard to answer.



IMO eliminating the source of the problem by no return to the intake is the only sure-fire method. Barring that, combining as many of the above listed treatment/preventative measures as possible would be wise I think. I have been impressed in particular with cars that have received the induction service. For those preventative measures I think starting early is important.

Might something like Amsoil Powerfoam work well for these problems. Pull the IM, fill the valve area, bolt it back up, wait, run the snot out of it, change the oil... (?)

Even better might be to use it as intended and simply fill the IM too, since the PCV return point is probably different in all of these engines.

I bet it would work better than some of the other induction services due to the contact of the foam with every surface in there, not just where some kind of mist in the air stream happens to pass by in just the right manner.

I totally understand, though, that most of these DI engines are in premium brand cars and everyone will not want to be the first to try something like Powerfoam in their shiny new BMW *35, especially under warranty.

I have 2 cans of Sea Foam that Im going to try misting through the intake at the filter neck. But, Im not having drivability issues so pulling the IM would be the only way to see before and after pics. I dont have the mechanical ability for that.

I do think the seafoam helps. I would suggest pulling it into the intake via the basketball needle method or misting it in somehow. I would go for as close as possible to the intake manifold and if you can't find a port or hose to put it in there then definitely post MAF sensor as I would guess the Naptha in seafoam could damage the MAF.

BTW, here is an old thread from Terry Dyson re: seafoam for recreational reading:

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=294035&page=1

Interesting info, would the CPO warranty cover any future issues caused by the deposit buildup?

I'm guessing issues with DI technology are mainly limited to FI, since I haven't really heard about any problems with Lexus DI for example.