roddylennox

Hi all,

There is a growing body of opinion that it can be beneficial to add two stroke oil to your diesel.

The logic is that relatively recently, the formulation of diesel has been changed for environmental reasons (reduction in sulphur content, which also happens to lubricate very expensive parts like fuel injectors and high pressure fuel pump).

So, to my question...I have a friend who has a 2012 Cayenne. An EGR valve has just failed. I suspect it may have been clogged up, as is often the case.

Anyone running 2SO in their diesel Cayenne? If so, what has your experience been with it?

Thanks in advance!

roddylennox

Anyone?

gnat

Ummm... I have no experience doing that, but that sounds like a bad idea.

With older diesels you could get away with all kinds of poor quality fuels (you could actually run some off kerosene!), but with finer tolerances in the more modern systems as well as the emissions cleaning systems those days are gone.

My fear with this idea is that it's not going to burn completely and will start to clog stuff up (as well as clogging stuff up before it ever gets the chance to burn). Additionally what does burn I expect will make the AdBlue system work harder since it would likely cause the exhaust to be out of the desired spec.

Finally, if you do have a fuel system related issue then Porsche is likely to check the fuel currently in the system. They probably won't look too kindly on finding 2SO mixed in just like they won't cover fuel system issues if they find you are using greater than 5% biodiesel.

tops911

I used it in my Cummins diesel, I swear I get a little better mileage and the engine is quieter (about a quart per 35 gals), but the Cummins is worlds different than a Porsche diesel

Twodan

I sometimes use 1 oz/gallon in my Duramax. Runs quieter is about all i can tell. In the winter, I add it when I use the anti-gel solutions.

DWPC

From the Porsche website: "The injection pressure (for the Cayenne diesel) is now up to 29007 psi ensuring optimum distribution of the air/fuel mixture..."

And I'm touchy enough about the 13000 PSI in my VW TDI fuel system. With an insane 29000 PSI fuel delivery pressure, paranoid me wouldn't put anything in the fuel tank not explicitly blessed by Porsche.

Needsdecaf

Yeah, putting oil in the fuel on an engine with these types of injectors strikes me as a good way to really foul things up.

aCayenneFan

Adding 2-stroke oil to diesel is voodoo chemistry. It probably would work with mechanical diesel engines, but not long term with the electronic diesels. At a minimum, it will probably result in shorter service intervals for the particulate filter. As others have posted, there may be problems with the injectors as well.

If OP is concerned about improving lubricity of the fuel, they should add biodiesel to the fuel. A 2.5% blend of biodiesel has been shown to get the lubricity spec of U.S. ULSD into the 400 micron range, which is the spec for Euro ULSD. Up to probably 10% blend of biodiesel should not result in contamination of the engine oil, but if you go beyond 5% biodiesel, I would confirm no contamination of the engine oil with a used oil sample at the 5,000 mile point.

grohgreg

Yeah, two-stroke oil can't be good for the DPF system. And FYI, the Cayenne owner manual limits biodiesel use to B5

//greg//

aCayenneFan

BMW started with a max of 5% biodiesel. They are now up to a 10% limit. Personally, I don't see a reason to go over 5%. It is not like injection pump or injector wear can be eliminated by increasing the biodiesel content; and then there is the additional wear of engine components that comes with contaminated fuel from higher biodiesel concentrations.

gnat

My understanding of the bio limits is because it gels much sooner and typically have more impurities (don't know if that is true for stuff bought from a gas station) which can lead to clogging up the filters and injectors. Everything I've read about people disregarding the MFG recommendations on newer engines and running higher B values (e.g. B50+) seems to confirm this.

The real benefit of bio has nothing to do with lubrication and everything to do with sustainability.

aCayenneFan

Maybe for home-brewed BD. I am only referring to BD that is distributed via a service station or other reputable commercial vendor. Home-brewed BD is NOT what I am talking about. The risk that occurs from running higher concentrations of BD is contamination of engine oil (from un-burned BD passing by the piston rings). Porsche is acknowledging this with their limitation to using B5.

Porsche could care less about sustainability when it comes to BD. They all have their sustainability initiatives, but substituting BD for dino-D2 is not high on the priority list. Hybrids and EVs get the CAFE results up much higher and sooner.

There are multiple tests that confirm the lubricity of biodiesel. Google or Bing are your friends in that regard. As far as sustainability, the un-subsidized cost to produce a gallon of D2 is lower than for a gallon of BD. Replacing dino-diesel with bio-diesel is kind of a Meh exercise, given the new supplies of petroleum. At some point, we may run out of petroleum, but I suspect it will be after you and I are long gone from this planet.