Here is the second analysis on my SAAB 900 turbo 16 with shell Helix Ultra Professional AV-L 0w-30.
OIL Shell Helix Ultra Professional 0w-30 AV-L
MILES IN USE 6440 (10362km), 6 months
MILES 386177 (621359km)
SAMPLE TAKEN 18/03/25 (date format for the civilized part of the world: 25.03.2017)
FILTER: Mann w712/80
wear metals (mg/kg)
WATER (%) <0.1
FUEL (%) 1.18
state of oil:
visc. @40°C (mm2/s) 56.62
visc. @100°C (mm2/s) 11.36
OXYDATION (A/cm) 1
NITRATION (A/cm) 0
SULFATION (A/cm) 0
dispergency* (%) 94
SOOT INDEX** <0.1
* the german word was "Schmutztragevermögen", hope I translated that right.
** the lab has introduced the "Rußindex", an in-house tool to check for soot in
gasoline oil, as soot from direct-injection engines will not show correctly in the
standard test for diesel oils
And here is the original report. From left to right: Shell Helix Ultra 0w-30 AV-L, Shell Helix Ultra 0w-30 AV-L, Shell Helix Ultra 0w-40 (twice).
Previous UOA: https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/4612694/Re:_Shell_Helix_Ultra_0w-30_AV
In direct comparison, you can see the effect of the residual oil - total oil volume is 4.5 litres, oil change volume just 3.8. So 0.7 litres stay in the oil cooler. In the first interval of the 0w-30, both viscosity and additive profile obviously have been skewed a bit by the residual 0w-40
. That is why I usually took samples only in the second interval with a new oil, but with the AV-L being so thin, I got a bit nervous last time.
All in all, I'm relatively pleased even with the second UOA. Wear seems normal, and the low ZDDP does not seem to hurt the flat tappets too much.
But I am more than impressed with the stability of the oil. Oxidation, Nitration sulfation - I have NEVER before seen values so low after a 10Mm-interval. I'm pretty convinced that I need not worry about sludge.
VI dropped from 204 (data sheet) to just 199, but that is probably due to fuel dilution, and not so much due to VII shear.
The proper UOA to compar eagainst would be the Aral Super Tronic 0w-40
- 1st, this OCI was also during the winter; 2nd, he Aral is also a low- to mid-SAPS oil; and 3rd, as a real "vollsynthethisch", that is >80PAO oil, the Aral should be clos to the benchmark in chemical stability.
I do not know what kind og whichcraft Shell is using with the AV-L oil, but it somehow seems to work.
If anything, than fuel dilution is going to limit the interval. Speaking of which, the experiment continues: for the first time, I did not change after 10Mm. I took a sample with a sysinge - and I did not change the oil.
10Mm already is an extended OCI - the factory prescribed 7500km, in severe service even less. A 15Mm-interval would double that. And 20Mm would 267%...
Yesterday, the odometer crossed the 625000km mark. The oil is now 14Mm in the engine. It is sloy getting dark, and oil consumption is starting to creep in. But oil level is sill slightly above the may mark on the dipstick (I overfilled slightly - 4 litres instead of 3.8). I will not use make-up oil in this interval. So, when the dipstick hits min, I shall change the oil, but I will not exceed 20Mm.
For a deeper discussion, see my blog: https://turboseize.wordpress.com/2018/04...tra-av-l-0w-30/
Text is in german, but google translate might help. If it doesn't feel free to ask - I'll do my very best to answer. [/quote]