Q regarding Diesel engine longevity in the U.S.....
 

As the title says, how many miles have been run up on Cayennes with the diesel engine in the U.S.? I am specifically interested in Cayennes in service in the U.S.A. There is a different lubricity specification for U.S. ULSD than for Euro ULSD, and I would expect Euro diesel edition Cayennes to do much better than their U.S. cousins.

Therefore, who has a diesel Cayenne with the highest odometer reading? Also, what have you had to repair along the way to your reading?

Thanks in advance to all who post.

Suggest you go check out the Touareg TDi forums or Audi Q7 forums. The second gen Touareg and the freshened TDi have essentially the same engine. It is slightly different, but for purposes of reliability, is similar enough to be a relevant look up.

Porsche has halved the oil change interval from 10k to 5k just for dealing with this reason.

You are asking about longevity for something that has been on the road less than a year and trying to ignore the versions that really do have longevity?

There is debate on if the 5k interval for change is warranted or if Porsche is being too paranoid. The TDI we have is structurally the same engine being used the world over by millions (billions?) of VAG cars. Its also a pretty old engine too (10 years I think with tweaks along the way). So there is no reason not to use the European or US sibling versions for the model you are trying to compile.

You'll always be able to find the bad apples, but overall this is a solid engine that will go much longer than most of us will own the cars.

I thought the 2013 was a newer engine and not the previous CATA engine. I thought the issues with all these past engines is not the engines but the latest NA emission requirements and premature failing emission parts. Buyer beware of the 2 year emissions warranty.
Good luck

Maybe I'm wrong, but I thought it was the same base engine with the appropriate modifications to add the DPF system as well as some ECU fine tuning to make it more Porsche-like.

Maybe I'm just inadvertently merging the VR6 and TDI V6 histories though...

Same Diesel engine in Touareg. Exact same one. Engine was improved to 240hp in 2013. I use Power Service (8oz) at each fill up to add lubricity...silver bottle 9 months a year and the white bottle in the dead of winter. I have a Touareg TDI and no issues at 28k...it's only 17 months old.

It's been debated here before, but the diesel is the choice over the V6 gasser for most driving situations. Pretty sure the diesel is now the top selling Cayenne power train. Looking to get a lightly used one with warranty to 100k within the next year mainly to get the excellent seats.

Interesting that VW does not have the oil change at 5k like Porsche.

I am not as up-to-speed on the different editions of the Cayenne/VAG TDI engines as I would like to be. Therefore the question about experience with the Cayenne.

Cutting the OCI is probably more a function of increased use of bio-diesel in the U.S. Bio-diesel in higher concentrations seems to be able to migrate past piston rings and contaminate the engine oil. With a potential for contamination, the best course is to increase the OCI.

Another option for lubricity is low concentration biodiesel. A 2.5% biodiesel blend gets the wear spec down to 400 micron territory, which is what Euro ULSD is spec'd at. Absent biodiesel, I would use PowerService. One additional reason to use PowerService is when the diesel you are using has a low cetane rating. PS bumps the cetane rating by about 4 points. In the S.F. Bay Area, Valero D2 has a cetane score ranging from 39 to 41. Chevron D2 has a cetane score in the range of 44 to 46. Higher cetane scores in my experience with the 335d result in better mpg. If Valero is less than Chevron, PS can level the playing field, depending on how much less.

That is kind of what I am looking to do as well.

That may change in the future. Especially with greater availability of biodiesel.

Good point about the cetane boost with Power Service. As for a lightly used CD, there available but go fast. Most are dealer demos.

I looked into this diesel fuel quality issue, and concluded the same -- my best bet was to use Chevron. Very easy to get in SF Bay Area. Haven't used any additives.

You should consider something for the lubricity issue if you want to keep the car long term. U.S. ULSD has a lubricity specification of around 520 micron wear (vs. around 420 micron for the Euro ULSD). If you don't add something to improve lubricity, you are rolling the dice on injection pump and injector failure.

There were some threads over in the VW TDI forums about injection pump failure in the 60K mile territory (engine basically grenaded). Porsche may have made some improvement to the injection pump and injectors to compensate for the reduced lubricity of U.S. ULSD, but I haven't been able to find anything published to that effect.

I try to time my fill-ups to hit area Shell stations, their D2 has a 46 rating. When traveling outside my local area, I refer to this list. I also carry Power Service next to the spare tire, for use in those occasions when 46 or higher is not conveniently available.

//greg//

My local stations don't show cetane rating in the diesel pumps. Am I ok using Exxon Mobil without the boost?

Been driving diesels since 1985, and have never seen a pump in America that identified the cetane rating. Octane rating are mandated on retail gasoline pumps, I see no reason that the same should not be required for diesel fuel. Unless the Feds consider all US-diesel to be "regular". In the EU there are three major classifications and quite a few sub-classifications.You can think of the big 3 as regular (40-50 cetane rating), mid-grade (51-59), and premium (60+). Regular isn't permitted for later model on-road vehicles. MY2000 and newer on-road vehicles typically use (minimum) 51 cetane.

By the way, the cetane rating is a number that represent how complete the "burn" is. The higher the cetane number, the more complete the burn. As burn rate increases, mpg goes up and noxious emissions go down. That's why adding a cetane booster to our crappy US-refined diesel returns both better performance and decreased fuel consumption. Another side note; Europe refines more diesel fuel than it actually consumes. Some of the excess is exported in tankers, and is what I believe we get at those very few stations in America that sell "premium" diesel (>50 cetane).

And to answer your question, I personally would add a cetane booster to every tank of American Exxon/Mobil

//greg//

I'm convinced -- just ordered a case of the product (Power Service -- Diesel Kleen + Cetane Boost) from Amazon -- QTY 12 -- 32oz -- good for 1200 gallons total or 30Kmi+ -- $77USD delivered. Here's a link to the Power Service web site that I found helpful: http://www.powerservice.com/faq/

Here's another thought. If one uses this additive, does it bring fuel quality up to European standards? And would it be prudent to extend oil changes beyond the recommended 5Kmi interval?