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The parts manager at my dealership insisted that the quart of Mobil 1 I bought from him yesterday was the correct. C40 oil. He is wrong. I didn't argue but this is an unknown issue at this major dealership and probably most others. I had my first (free) oil change done there and unless they are using C40 from a special drum in the service area I have a engine full of dealer-installed A40 as does every other new Porsche in the service bay. PCNA must know of this and they are apparently unconcerned, as am I.
Howard
The fact that dealers are actively filling these cars with the incorrect oil is an absolute joke. If PCNA can agree with PAG that A40 is just fine given we (North America) don’t have active OPFs then that’s dandy, but as it stands the owner’s manual spec is C40 and until that time (if even), then I am going to damn well expect C40 is what gets put into the car. Further insult to injury, people are paying obscene dealer oil change prices to get unapproved spec oil put into these cars.
I will tell you, if I am going to pay dealer pricing for an oil change I am going to watch them pour C40 down the gullet with my own two eyeballs, otherwise they can go pound salt and S a D at the same time.
Last edited by Jim Rockford; 12-31-2020 at 08:54 PM.
Sorry, I doubt that. There are almost certainly differences in the add pack that are unique to the C40 formulation that would be easy to determine through analysis. Most additives are not consumed during the interval.
I'm a former oil distributor for Exxon, attended lots of seminars put on by their engineers, and while I don't know the difference between the two oils, it most likely is the add pack. It is possible to pull samples to determine one from the other, but it is expensive, much more than a mere oil analysis like Blackstone, etc. I very much doubt a dealer just will not do this and before PCNA is CV involved the oil would be long gone. And if lots of the cars are really getting A40 then it's pretty much moot . Now yes, C40 protects better against LSPI, which is more prevalent in DFI cars with the piezoelectric injectors apparently, but I have to wonder if the knock detectors dont also guard against this? Still a lot of confusion and uncertainty.
The car manufacturer's oil specifications present a performance standard which must be achieved through a large series of destructive bench tests for example cam wear, cam pitting, sludge tests, piston cleanliness etc. They do not specify the additive pack other than a minimum TBN - it's up to the oil company / blender to work with its additive pack provider to formulate an oil to meet the requirements and pay fairly hefty sums to put it through the tests required to support their application for manufacturer approval - well into the hundreds of thousands of €/$/£.
Following from Bill's post above, I would tentatively agree that if you sent two used oil samples, one C40 and one A40, back to the oil manufacturer, then they could devise a method to determine which was which based on tests for certain additives. However, the complication is different oil companies use different additive providers - Exxon might use Infineum, others may use Lubrizol. So if an independent lab is trying to determine if an oil is C40 compliant without knowing what they are looking for, the chances of making a definitive conclusion are very low IMO.
If you go to the Lubrizol relative performance tool, you can see that C40 has a higher performance standard for the soot thickening, sludge and piston deposit tests than A40. Hopefully VW 511 00 will make its way into the Afton Specification Handbook next revision and the details of the tests (VW 511 = C40) will be more readily accessible.
Actual data to differentiate the C40 oil, thanks Steve9!
Wondering if Mobil and other brands have similar info, but this certainly makes me think thrice about A40. Now to sourcing C40 in Canada...
No thinking, C40 or bust!
See my post above (#128), I always do a preemptive oil change after break-in, this time I had to be a little more resourceful, the hint for the source is the watermark over the picture of the oil...
Would be interesting if anything in the C40 spec helps reduce carbon deposits on the intake valves? That would certainly keep the engine running at peak efficiency and likely help with emissions as well.
From that diagram above comparing A40 and C40, it is not even close. The C40 is far superior than A40 especially in the soot thickening (I had to look up what this meant from an oil perspective). Sludge and Piston deposit is marginally better but still important.
I would ask specifically whether the dealer actually has C40 oil. It is fine if they don't because we can always bring our own oil.
12-31-2020, 08:49 PM
