DI engines and coaking

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I remember a few threads a few years ago where the (then) new Direct Injction engines (from Audi and others) were showing unusual coaking of the intake valves even when proper oils and OCIs have been followed. Can anyone comment on the current state of these kinds of engines and oil? And whether the new updates with turbos (and supers) ameliorate or deteriorate the coaking problems?
 
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Not seeing as many posts on this so maybe it's less of a problem, although the Mazda guys complain about it a lot on the Turbo DI engines in the MS3/MS6. Purely IMO, two oil related fixes to this: Low SAPS such as VW507 such that when it ends up in the intake tract through PCV/EGR, it doesn't make ash deposits, or... Oil with extremely high HTHS such as Redline 5w40, that doesn't evaporate in the first place, making low/high SAPS irrelevant.
 
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I've been hearing that it's only a problem with cheap/low octane gas, overextended OCIs, and/or bad oil choice.
 

JRed

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Coking on turbochargers isn't a problem these days. Direct Injection? Jury is still out. I'd avoid it for a few more years just to be sure.
 
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Originally Posted By: d00df00d
I've been hearing that it's only a problem with cheap/low octane gas, overextended OCIs, and/or bad oil choice.
Sorry, but I know someone with a 2009 MY vehicle who uses 93 octane and changes oil religiously who had to have the engine de-carboned at 30,000 miles.
 

gathermewool

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Originally Posted By: cchase
Originally Posted By: d00df00d
I've been hearing that it's only a problem with cheap/low octane gas, overextended OCIs, and/or bad oil choice.
Sorry, but I know someone with a 2009 MY vehicle who uses 93 octane and changes oil religiously who had to have the engine de-carboned at 30,000 miles.
What oil?
 
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Originally Posted By: cchase
Originally Posted By: d00df00d
I've been hearing that it's only a problem with cheap/low octane gas, overextended OCIs, and/or bad oil choice.
Sorry, but I know someone with a 2009 MY vehicle who uses 93 octane and changes oil religiously who had to have the engine de-carboned at 30,000 miles.
what kind of car.. without the type of car your post isnt very useful or informative.
 
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Originally Posted By: Brons2
Not seeing as many posts on this so maybe it's less of a problem, although the Mazda guys complain about it a lot on the Turbo DI engines in the MS3/MS6. Purely IMO, two oil related fixes to this: Low SAPS such as VW507 such that when it ends up in the intake tract through PCV/EGR, it doesn't make ash deposits, or... Oil with extremely high HTHS such as Redline 5w40, that doesn't evaporate in the first place, making low/high SAPS irrelevant.
Originally Posted By: d00df00d
I've been hearing that it's only a problem with cheap/low octane gas, overextended OCIs, and/or bad oil choice.
Nope. The 4.2L FSI V8 is still having these issues. The 2.0TFSI is still having it from what I see, though I don't know if anything was changed in 2012 or 13. The newer 3.0TFSI V6 (supercharged) used in lots of their cars has remedied this with a new PCV and EGR system, and some sort of new oil reclamation system. I have some Audi technical docs that detail it. Photos posted on the various Audi enthusiast sites have shown no buildup at 40k+. It has very little to do with oil choice or change interval, as the RS4 guys do not run 10k OCIs and have tried almost every oil under the sun. Catch cans do very little too. The buildup is lessened with the special RLI 5w40 but yearly cleaning is still needed...some of those guys posted before/after dynos to show nearly 25% of the engine's power being lost to the buildup!
 
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Originally Posted By: dparm
Nope. The 4.2L FSI V8 is still having these issues. The 2.0TFSI is still having it from what I see, though I don't know if anything was changed in 2012 or 13.
To be terribly blunt, it does seem like a nuisance, but it's something I could live with if it were a reasonable, DIY cleanup that could be accomplished in an afternoon and without opening a can of worms with respect to warranty issues. Regardless of how much money someone has, having to take such a thing to the dealer on regular intervals is a huge nuisance. I'd have to look in my back issues, but C&D reported one of the recent FSI Audis on a long term test with an increase in power over the 30,000 mile test, with no mention of buildup cleaning in their story. They followed manufacturer OCIs to the letter, since that's what they do.
 
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Originally Posted By: d00df00d
I've been hearing that it's only a problem with cheap/low octane gas, overextended OCIs, and/or bad oil choice.
Don't see how low octane gas has anything to do with it since the injectors are nowhere near the intake. Anyway, it's not an import but I've got a 2010 Taurus SHO with the Ecoboost 3.5 that has a hair over 41k now. Always use the cheapest gas I can find (it runs fine on regular), follow Ford's 7500 mile OCIs, and it still has plenty of power, idles super smooth, and is generally fine. MPG could be a bit better but I like to use the owner I paid for. smile. However on a straight highway I can get near 26 MPG so I'm happy there.
 
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I run premium, use good synthetics on short OCI's, drive it hard, get 30 mpg combined, but only at 15K miles so at 30K I'll let ya' know....
 
Originally Posted By: itguy08
Originally Posted By: d00df00d
I've been hearing that it's only a problem with cheap/low octane gas, overextended OCIs, and/or bad oil choice.
Don't see how low octane gas has anything to do with it since the injectors are nowhere near the intake. Anyway, it's not an import but I've got a 2010 Taurus SHO with the Ecoboost 3.5 that has a hair over 41k now. Always use the cheapest gas I can find (it runs fine on regular), follow Ford's 7500 mile OCIs, and it still has plenty of power, idles super smooth, and is generally fine. MPG could be a bit better but I like to use the owner I paid for. smile. However on a straight highway I can get near 26 MPG so I'm happy there.
Ditto. My 2010 SHO (non Performance Package) also runs fine on regular and also gets 26-27 mpg on the open road.
 
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Originally Posted By: Garak
Originally Posted By: dparm
Nope. The 4.2L FSI V8 is still having these issues. The 2.0TFSI is still having it from what I see, though I don't know if anything was changed in 2012 or 13.
To be terribly blunt, it does seem like a nuisance, but it's something I could live with if it were a reasonable, DIY cleanup that could be accomplished in an afternoon and without opening a can of worms with respect to warranty issues. Regardless of how much money someone has, having to take such a thing to the dealer on regular intervals is a huge nuisance. I'd have to look in my back issues, but C&D reported one of the recent FSI Audis on a long term test with an increase in power over the 30,000 mile test, with no mention of buildup cleaning in their story. They followed manufacturer OCIs to the letter, since that's what they do.
It is not a simple job. http://www.audizine.com/forum/showthread.php/389969-Official-RS4-Carbon-documentation-thread Garak, which FSI motor was it?
 
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Originally Posted By: Audios
I thought the fact that the injector doesnt wash the back of the intake valve added to the situation as well.
This Oil Catch can, 3k OCI's and EGR delete PROLONG it.... Nothing is maint free on a DI for sure.
 

Mitch Alsup

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Can I take from this discussion, that a DI engine with a dry sump (and cone deareator) will be less likely to suffer from coaking than a typical wet sump with PCV and EGR?
 
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It's a problem on some n/a Audi Q5's with the n/a V6. VW/Audi's next update to the 2.0T will have direct and port injection. Hopefully that will help along with the PCV and EGR revisions that dparm mentioned. Although I don't think it was as bad of a problem in the 2.0T's anyway. From Car and Driver:
Quote:
The head also incorporates an integrated exhaust manifold with its own cooling circuit, similar to VW’s new EA211 engine series. Like that smaller engine family, the EA888 isolates the coolant in the head to more quickly warm up both the engine and cabin. Engineers also told us that, because they flow through a water-cooled manifold, exhaust gases are 158 degrees cooler by the time they reach the turbocharger. The EA888’s water pump is driven off of the left-side balance shaft, removing an auxiliary from the usually cluttered front end. Like some Toyota engines, this Audi powerplant family uses both direct and port injection. Direct injection is used to stabilize the idle and in full-load situations, while the port injectors are put to work under partial loads, where Audi engineers say port injection is better at mixing the fuel and air, with less soot produced and reduced CO2 emissions compared to direct injection. Unlike the Toyota setup, this engine operates either as a port-injected engine or a direct-injected one, and never uses both injectors simultaneously. The third-generation EA888 is said to be about 11 pounds lighter than the second gen, despite the wealth of new features.
-Dennis
 
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Originally Posted By: SteveSRT8
It would have a few other factors involved but overall I would say yes. A lot of this issue is simply revealing the volatility of the oil used.
Pennzoil has said that the use of certain VIIs cause buildup as well. The RS4 guys tried oils with very low NOACK and didn't see much of a difference. Granted, it is hard to measure.
 
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