Mobil1 0w20+0w30 mix. 7000 miles '01 Subaru 2.5L

[oilyriser]

recent sample listed to the left
engine has about 55,000 km on it

code:

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2004/06/13, 2003/09/25

Mobil 1 0w20/0w30 mix 11123km, 7926km Tech2000 10w30

Dec-Jun, Jul-Oct



Fe 12 5.3

Cr 1.4 0.8

Ni 0 0

Ti 0 0

Ag 0 0.3

Al 6.4 2.8

Pb 1.6 0

Cu 1.9 3.0

Sn 0 0

Si 11 9.9

Na 5.7 0

K 0 0

B 133 3.0

Ba 0.2 0.4

Mo 67 1.2

Mg 29 11

Ca 2709 1969

P 771 850

Zn 1009 970

S 1938 3052

Mn 77 116

V 0 0

Fuel -- 0

Gly -- neg

Oxi 82 42

Nit 63 31

Sul 73 52

TBN 5.22 4.40

Kv40 52.8

Kv100 10.2 10.4

VI 185 --

H2O neg neg

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The oil was a mix of 2qt 0w30 and 2L 0w20. Filter was Supertech 3593, and it's ADB valve worked well for the entire time. I had to retighten it once to stop a slow leak.

The starting viscosity should have been about 9.3 cSt @100C, so it thickened up a bit. I wanted to see if one could fill with a thin oil at the beginning of winter, and have it thicken up automatically, in time for summer. Its viscosity index stayed high, so I suppose it might still qualify as a 0w-xx oil.

Does anyone know how to interpret the Wearcheck particle count graphs? The graph from this time looks identical to the one from last time, too.

The engine makes the piston slap noise in winter, and I wanted to see if the pistons were shedding any aluminium.

There was lots of magnetic powder on my drain plug magnet.

Oxidation might be the limiting factor for extended use here, since TBN is still quite good.

I drained this stuff, and filled with a 5w20/5w30 mixture of a brand that begins with the letter R.

[ June 23, 2004, 12:10 AM: Message edited by: oilyriser ]

 

[jthorner]

Obviously a very different driving season for the two runs, but at first blush there doesn't seem to be any reason to prefer the Mobil-1 brew over the Tech2000 you used previously.

John

 

[Patman]

quote:

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Originally posted by oilyriser:



Does anyone know how to interpret the Wearcheck particle count graphs? The graph from this time looks identical to the one from last time, too.

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I've never been able to figure out those graphs, every single one I've gotten from Wearcheck, in every single car, looks identical.

 

[Al]

Very interesting and informative. Again-high iron with Mobil 1. The Suertech more than held its own against Mobil. Amazing bearing wear.

. In spite of its low tech formula-the Supertech Oil has given good results here and on other posts.

I'll look forward to your test on the oil that starts with "R"

. I have a 50/50 mix (5W-20/10W-30 ) of Redline in right now.

Great Post

 

[Cutehumor]

quote:

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Originally posted by Al:
Again-high iron with Mobil 1.

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It makes you wonder with the mobil 1 commercials out right now saying that running mobil 1 in a car with 200k miles showed "virtually no wear" is the virtually part the high iron?

 

[giant_robo]

quote:

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The engine makes the piston slap noise in winter, and I wanted to see if the pistons were shedding any aluminium.

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Maybe it doesn't like the thin weight oils, 0w20!! Don't you think a 5w40 synth or 5w30 could be a better choice?

If you ignore the fact that you have harder winter conditions, it would seem the good old 10w30 performed better, by over a factor of 2, for all metals except Cu.

[ June 26, 2004, 02:50 AM: Message edited by: giant_robo ]

 

[oilyriser]

10w30 silences the piston slap in winter quite well, but when it gets down to -28, I like the 0w-30 stuff.

The iron wear isn't serious for 7000 miles and winter conditions, but it's the high oxidation that bothers me. I expected Mobil 1 to be more resistant to oxidation than the cheapest oil on the market from Wal Mart. And shouldn't oxidation be worse in summer, when temps are higher?

The Mobil 1 was at 80% of the allowable limit for oxidation after 7000 miles, while the Tech 2000 was only at 40% after 5000. Maybe if I took the Tech2000 to 7000 miles it would be the same. I talked to Gloria at Wearcheck, and she said their instruments do give correct oxidation numbers for Mobil 1.

The oil thickened by more than 10%, so I suspect the oxidation #'s to be correct. It was kind of nice, though, to see the oil thicken to #30 viscosity just in time for summer. This is what I had hoped. TBN was still good, but I want things to stay clean.

I'm going to ask if they have any of my samplke left, so they can centrifuge it and give me a %insulubles number.

Mobil 1 in this car is only good for 7500 miles, it seems. I might start using something else, if I know the oil is staying clean enough.

 

[TooSlick]

I noticed the new 4/6 cylinder, Sube boxer engines both use moly coated piston skirts, perhaps to address this piston slap issue.

I'd like to know how the cylinders are lubed, since they are horizontally located?

TS

 

[oilyriser]

My old engine's pistons had a black coating on the sides, and it did not have a loud piston slap. I'm not sure about the new one. A piston in the old engine snaped in half, so that's why I got to see inside.

Maybe oil flings off the crankshaft and gets into the cylinders.

I've been wondering if I could hydrolock this engine by parking the car at an angle. Maybe after a few weeks, enough oil will seep past the rings to fill the combustion chambers, if the level is high enough.

Overfilling this engine with oil could be a very bad thing.

 

[Jay]

I wouldn't take Wearcheck's Ox and Nit readings too seriously. Gloria told you correctly.

As for the particle count graphs, they should slope from left to right. That is, there should be fewer big particles than smaller particles. A left to right slope indicates normal wear. A right to left slope indicates abnormal wear and impending failure.

 

[Patman]

I have never trusted the oxidation and nitration numbers from Wearcheck. Especially when I took a very early baseline sample at 700 miles in the fall of 2002 when I first switched to Schaeffer Oil, and the oxidation was over 40%. Impossible.

I honestly don't pay any attention to those values in my reports. Even Terry told me their numbers for ox/nit looked to be double or even triple what they should be.

 

[Al]

quote:

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Originally posted by Patman:
I have never trusted the oxidation and nitration numbers from Wearcheck. Especially when I took a very early baseline sample at 700 miles in the fall of 2002 when I first switched to Schaeffer Oil, and the oxidation was over 40%. Impossible.

I honestly don't pay any attention to those values in my reports. Even Terry told me their numbers for ox/nit looked to be double or even triple what they should be.

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I agree..Schaeffer's labs are not reliable either except possibly on their own oil.

 

[oilyriser]

The oil did thicken, so there was some oxidation. The recycled oil probably sheared and thickened at the same time, so the visc. stayed the same. Can I extrapolate the thickening and figure out how long I could go until it thickens by 20% and then dump it according to that? But it's a very non linear function... I've looked at those graphs where it suddenly thickens a lot after a certain point.