Fuel adatives....

[Andyuk911]

Dave, did you see much smoke out the exhaust during application ?

[PetrolDave]

Dave, did you see much smoke out the exhaust during application ?

Quite a bit!

[RS04COM]

That oil has no tested certifications including VW 502 or 504...not even API SA.

Correct.

Just take a look at the valve deposit photos in this thread to see how well 502 or 504 oils are working for you.

If you have a deep enough pocket to pay the bills when Audi say that a new engine is not covered under warranty then good luck to you. Personally I'd rather stick with VAG approved oils - even if it means Audi get a big bill. At least they'll get the bill and I won't.

Personally I am considering selling the car after only 21 days due to this issue as the idea that my 'state of the art' engine has progressive Asthma through a design that is not fit for function makes my p**s boil!

Ignorance is bliss!

[SR71]

My UOA came back from the US showing high levels of Fe & Al along with fuel dilution and soot.

The recommendation is to get my inlet cleaned ASAP and start using RLI Bio Synth.

I will be writing to Audi UK.

How are Porsche DI engines bearing up? Does anyone know?

[ArthurPE]

My UOA came back from the US showing high levels of Fe & Al along with fuel dilution and soot.

The recommendation is to get my inlet cleaned ASAP and start using RLI Bio Synth.

I will be writing to Audi UK.

How are Porsche DI engines bearing up? Does anyone know?

what % dilution?
how many miles on the oil?

the independent testing lab made a recommendation to have the valves cleaned?
how do they know about the issue without inspection?

they recommended you use a specific brand of oil not approved by the manufacturer (or any major testing or standards organization) and may cause warranty issues?

what lab was this?

[PetrolDave]

Personally I am considering selling the car after only 21 days due to this issue as the idea that my 'state of the art' engine has progressive Asthma through a design that is not fit for function makes my p**s boil!

Ignorance is bliss!

You had better not buy ANY car with direct injection then...

there are two root causes IMHO:

1) direct injection means there is no fuel vapour in the inlet so it runs dry.

2) the oil vapour separator design is inadequate.

[Teutonic_Tamer]

1.5 to 2% fuel dilution is low and pretty much typical...
in a 10 qt engine sump if the level stays the same that means you lost only 6.4 oz, 1/5th of a qt...negligible...

gas is volatile, it's vapor pressure is much lower than oil...so it 'cooks off' and is aspirated/combusted into the engine, the vapor would actually help clean the valves...ever see it spilled on hot asphalt? vaporizes very fast...

it's also got a lower density, so it passes thru the cyclone with a higher efficiency...where as the oil drops out...

I think the problem is the cyclone seperator...the cyclones don't work right, the sequencing valve, bypass valve, pressure regulating valve, something is sticking/gumming up, and not seperating the oil entrained air properly...

I'd like to see someone stick a simple baffle/filter on the output tube of the cyclone module and see if this helps...

the valves get very hot, that's why the oil cokes or 'tars' on them...

Arthur,

Sorry, you're wrong. All of these fuel dilution measurements were performed on oil that had been extracted after the engine was run at highway speeds and reached operating temperature to allow maximal burn off. Peak fuel dilution is most likely in the 3-4% range otherwise. It's possible, but unlikely that Audi and VW have both missed an obvious issue with the cyclonic separator on engines lines like the 2.0 TFSI that have been in service since 2005.

These fuel dilution levels correspond to oil flashpoint measurements of 290F down to 230F, and are not normal for most gasoline engines. (The flashpoint is the point at which oil begins to vaporize.)

Erm, no it isn't. Flashpoint is simply the lowest temperature that a vapour above a liquid is able to be ignited. Oil vapourisation can occur at temperatures both above and below the flashpoint

Given that the engine operating temperature is normally in the 230F range, on average, under spirited driving rising to 270F plus, and recognizing that the local temperatures are even higher, it is not surprising that a significant amount of oil is vaporizing, along with the fuel, with some significant percentage passing through the cyclone separators. As long as the effective condensation point (pressure/temperature) of the diluted mixture that volatizes is higher than the expected designed maximum on the separator, the oil is going to pass right through. I expect that Audi and VW engineers who contracted this design out did not account for chemical attack on the oil by aromatic hydrocarbons in the fuel.

It was this specific reason why the 504.00 standard was developed - it includes a very specific 'FSI test sequence'!

Certainly the separator could be redesigned, but this would require that more "bad stuff" be recycled back into the oil to contaminate it.

Not only do we see this issue from fuel dilution, but also we see significant deterioration of the ZDDP tribological layers intended to protect the bearing surfaces in the engine, as evidenced by increase Fe wear during high fuel dilution and increase of the amount of free Phosphorus in the oil.

Again, with respect to 504.00 oils - with them being 'low SAPS', then they are also low on ZDDP to start off.