Elf Excellium DID 505.01 5W40, Jetta TDI-PD

[fitzski]

Here's my most recent UOA's from the Jetta:
Vehicle: 2004 Jetta-PD
Mileage at time of sample: (1) 119,555 km (74,288 mi); (2) 127,665 km (79,327 mi)
Mileage on oil sample: (1) 16,147 km (10,033 mi); (2) 24,257 km (15,073 mi)
Analysis lab: CAT (Toromont)
Oil: Elf Excellium DID 505.01 5W40

Notes: No oil was added during interval; level fell from top of hash mark to not-quite-bottom of hash mark. Everyday driving - winter starts, stop-and-go commuting. Unfortunately, no TBN analysis on the later sample, and none of the FT-IR analysis of the first (which is reported in "UFM"...?). Oil was changed after the latter sample, and I put in the last of my DID. Still very pleased, and will almost certainly run 25k before the next OCI (though I'll do a UOA at 16k and evaluate).

Results:
Code:
(1) (2)

KM: 16147 24257

Fe: 40 40 (hmmm.....)

Rate: 3.99 2.65 (Fe/1000 miles)

Cr: 1 1

Pb: 3 3

Cu: 3 3

Sn: 1 0

Al: 5 5

Ni: 1 1

Si: 4 4

Na: 11 11

K: 3 3

Zn: 936 886

Mg: 22 19

P: 1029 886

TBN: 7 --

Soot: -- 25

Sul: -- 23

Nit: -- 12

Oxi: -- 20


For the soot, and other FTIR measures, I have no idea how to interpret/relate the numbers. Very frustrating, as I can find little to no cross-reference. The UFM quantification apparently comes out of ASTM E2412 (Standard Practice for Condition Monitoring of Used Lubricants by Trend Analysis Using Fourier Transform Infrared (FT-IR) Spectrometry):
http://www.astm.org/cgi-bin/SoftCart.exe/DATABASE.CART/REDLINE_PAGES/E2412.htm?E+mystore

Save for the iron, the 2nd analysis seems reasonable: an "appropriate" reduction in the additive package elements, and with the other elements being such trivial numbers, I wouldn't expect to see much/any difference. A change of a point (in either direction... i.e. the Tin) is probably well within the tolerance/margin for error.

For the iron... I'm not sure. Puzzling, and does make the UOA questionable, IMO - no change after 8k km of winter driving?? One factor may be the use of the coolant heater contributing to the efficacy of the oil on cold morning starts.

Sampling is by vaccuum pump, BTW.

 

[wjdell]

fitski - I cant find it but if you write SunRG he ha the conversion 25 is low like less than .2% IIRC.

 

[fitzski]

I checked with the lab, re: UFM. This is what they replied with:
"As per the 'UFM' numbers, your car being a diesel would have specific limits in terms of soot, oxidation, nitration and sulphation. The limits are 30, 34, 12 and 34 respectively."

They didn't comment on relating the values to the typical % allowable, or absorption units (though I specifically asked).

I also inquired about margin of error (given my Fe over the last two samples):
"In terms of our 'margin of error' in sample results, this would differ depending of the test. In our elemental analysis, our margin of error is approximately +/-2ppm."

I also found this answer surprising given that I was expecting a percentage error, rather than an absolute.

I suspect they are probably over-simplifying for my "benefit" and trying to get a response out quickly.

 

[Lumberg]

Look, if your numbers are below 26, 30, 8, & 30, I wouldn't worry about it.

 

[Lumberg]

Looks like Nitration is your only problem on that front. What causes that? Higher combustion temperatures (actually can help mileage if managed properly)?