Mobil 1 SS 10wt/30

['00obw]

Sample analysed by OAI/CTC on 17Mar'03

Vehicle: '00 Subaru Outback Wagon AWD with AT and 2.5l engine. Puchased used in Oct'02 at 12,375 miles.
Oil: Mobile 1 SS 10wt/30 installed 12Dec'02 at 14,335 miles, previous oil is unknown. Factory recommended oil is 5wt/30. Sump capacity is 4.2qts.
Oil Filter: OEM, made by Purolator, installed same time as oil, previous filter is unknown.
Air Filter: OEM, I presume.
Miles on Sample: 3,503.
Miles on Vehicle at Sample: 17,838

Winter here was mild, rare lows below 40*F and some highs reached 80*F+. A workweek is 5 1/2 days. During a normal workweek, I rarely drive more than 15 miles a day, work is a 2 mile drive and all city-type conditions. If I go over the 15 miles its to my "big cities" and thats my hiway miles but only about 30 miles roundtrip. I do that about once a week. On my days off, I sometimes take drives of 100+ hiway miles otherwise its just running local errands.

During this sample period, alot of the 3,503 miles were from the Xmas holiday period where I made 4 trips of 450+ miles duration. The last 2 months were of my normal weekend driving. Best guess is I drive 400 to 600 miles a month.

Okay, here's the numbers...in ppm.

Iron 5
Chromium 0
Lead 2
Copper 1
Tin 0
Alum 2
Nickle 0
Silver 0
Silicon 4
Boron 149
Sodium 0
Mag 29
Calcium 3026
Barium 0
Phos 1044
Zinc 1157
Moly 79
Titanium 0
Vanadium 0
Potassium 0

Fuel Vis@40C n/a
Vis@100c 9.69cSt
Water 0
Glycol Neg
TBN 5.86
Oxid 49.0
Nitr 22.0

From lurking and learning in this very informative NG, I think I can safely say I wont have to change the air filter yet, the wear numbers are low and the oil may have life to go another 2 months...at my driving rate.

TIA for any comments and suggestions as they will be greatly appreciated....bgin

 

[Al]

Certainly nice numbers-as good as any we have seen from the 5w30. TBN and Oxidation are getting down to the end but you are good for a couple months at your driving rate. However the viscosity is thinning out as the 5W stuff does so after 2 months and in the heat of Cali- I would go for the 10w30 Mobil (I know I'm a broken record on this issue

)
Thanks a lot for posting and nice report.

 

[Patman]

quote:

---

Originally posted by Al:
Certainly nice numbers-as good as any we have seen from the 5w30. TBN and Oxidation are getting down to the end but you are good for a couple months at your driving rate. However the viscosity is thinning out as the 5W stuff does so after 2 months and in the heat of Cali- I would go for the 10w30 Mobil (I know I'm a broken record on this issue

)
Thanks a lot for posting and nice report.

---

Al, he did run 10w30 actually. He says that 5w30 is the recommended oil, but that this report is with 10w30.

It is a very good report indeed.

The oil didn't thin out really, 10w30 M1 starts at 9.8. Had it been 5w30 as you assumed, keep in mind their 5w30 starts at 9.7, so it would not have been thinner as you assumed, it would've been right on target.

 

[nicrfe1370]

'00obw

That is an absolutely outstanding report. The wear numbers are lower than any report on any Subaru I've seen.
If you wanted to compare your results to other Subaru's, go to my Microsoft Excel spreadsheet at http://home.earthlink.net/~jabrande/oilanalysis/SubaruTrend.xls

 

[sprintman]

I have MY00 Outback too. Your spreadsheet makes interesting reading. Not sure now whether to stay with Redline or go to M1 SS (when it finally arrives in Oz). Tks for posting...s

 

[Al]

quote:

---

Originally posted by Patman:

Al, he did run 10w30 actually. He says that 5w30 is the recommended oil, but that this report is with 10w30.

---

Yike

Help me!! I fell down and can't get up

Thanks. No wonder it was such a good report-with the 10W stuff

Thanks TooSlick- I guess TBN is not TBN

[ March 19, 2003, 07:52 PM: Message edited by: Al ]

 

[TooSlick]

Al,

Don't forget this is a CTC analysis, so TBN is done using ASTM D-4739. Blackstone would show a TBN of approx 7.5 for this same sample. I'd step out to a 5000 mile change interval on this one ....

TS

 

['00obw]

Thanks for all the comments. The things I haven't gotten to understand yet are the oxidation and nitration numbers. Can someone please explain them to me?

Thanks....bgin

 

[Patman]

quote:

---

Originally posted by '00obw:
Thanks for all the comments. The things I haven't gotten to understand yet are the oxidation and nitration numbers. Can someone please explain them to me?

Thanks....bgin

---

Here is an email I saved on the subject, but I can't recall who it was that sent it to me (it was either Bob, Terry or MoleKule)

1. Oxidation - oxygen interrupts or attacks
the hydrocarbon bonds and breaks them up at high temperatures, turning
the molecules into sludge, varnish and
lacquer. Synths have stronger molecular bonds and better molecular
arrangements than do dinos, since synths were
engineered to do that. Hence the better oxidation resistance, wider
VII, and greater film strength.

2. Evaporation - when a material transitions
from its liquid phase to its vapor phase due to heat. In dino oils, you
have
molecules of all sizes; the lighter ones will
evaporate leaving behind the heavier ones, the heavier ones contributing
to
sludge. This is why your viscosity increases
in dinos when evaporation is high, and it also loses its lubricity. In
synths,
the molecules are consistently longer,
stronger chains that resist boiling off at high temperatures.

Both oxidation and evaporation are caused by
heat, and both can contribute to sludge, varnish, lacquer, and increased
viscosity. In full synth's, the stronger, more
consistent molecule is more resistant to heat, evaporation, and the
breaching of its film.


Nitration results from the heating of O, O2, N2, OH, and H in the
cylinder during combustion. The separate gasses mix
and when burned, form many resulting gasses
including NOx.

NOx generation is highest during: high
pressures, high temperatures, during crank angles between 10 and 40
degrees, and when the A/F ratio gets near
16:1, such as in lean-burn engines.

NOx gets into the oil via the blow-by gasses
during the power cycle when the cylinder pressure is highest and when
when the temp of the buring gasses is highest.

EGR valves and large overlap cams introduce
exhaust gas back into the cylinder to cool it down, reducing generation
of
NOx.

NOx creates peroxides that attack the oil and
increase oxidation as well..

[ March 22, 2003, 12:55 PM: Message edited by: Patman ]