1998 BMW 528 137,288km, 8,118km 6mth, GC Green

[Craig in Canada]

1998 BMW 528i
137,288km on unit
8,118km on oil
0qt makeup
GC 0W30 Green (mix of M04, M050)
LC20 used at OC and for half of the OCI
FP60 used in fuel

Fewer long trips, more short trips than previous use of the vehicle.

UOA HERE

Previous Wearcheck UOA on M1 0W40 (not previous OCI) at HERE

To me the 100C Viscosity seems a little low for GC. GC is supposed to be pretty shear stable. I'm not sure if the fuel dilution is throwing that off or what's going on there. GC should be just over 12, no?

Craig.

 

[e36'n]

Looks great except for the shearing. Any modifications or track events?

 

[Craig in Canada]

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Looks great except for the shearing. Any modifications or track events?

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No engine internal mods, but it does have Dinan Stage 3 software, Dinan throttle body, Dinan exhaust, stock air filter, stock plugs. No track time (and not a car that begs me to take it there). Suspension is a mixture of stock and modified but that won't affect the oil.

Since recent family additions, my wife uses it most. When I'm driving revs are higher and it breathes deeper. As I mentioned, more short trips (wife/child errands) and fewer long trips. This car has never been used for daily commuting.

I can't remember if it was viscosity results from Blackstone that people were calling into question a while back or something else. I am really surprised if GC actually sheared that much in this vehicle at this OCI. I don't think there's enough fuel to account for it.

Craig.

 

[JAG]

It was fuel measurements that were called into question. I wouldn't worry about the viscosity measurement or anything else since this UOA is really good.

 

[Craig in Canada]

Worried? No. Curious? Yes.

 

[Quattro Pete]

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To me the 100C Viscosity seems a little low for GC. GC is supposed to be pretty shear stable.

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It did not shear out of grade. Whatever it did is most likely due to the fuel dillution. I don't see how you can blame the oil for it though.

 

[Craig in Canada]

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To me the 100C Viscosity seems a little low for GC. GC is supposed to be pretty shear stable.

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It did not shear out of grade. Whatever it did is most likely due to the fuel dillution. I don't see how you can blame the oil for it though.

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Would "trace" fuel dilution impact the viscosity that much? I don't have a good quantitative feel for how much fuel it takes to cause that sort of thing.

 

[JAG]

What Blackstone calls trace isn't always truly trace. Maybe I should say that's my opinion so I don't get in trouble for saying it. 427Z06 posted calculations of % fuel vs viscosity of some oil/fuel mixture but i can't find it. I think that bruce381 recently did as well in this forum but I have not searched for that myself. If you can't find that, you can use a free online viscosity mixture calculator and do some calculation to find how much fuel it would take to get the viscosity that Blackstone measured. Then see if it makes sense.

 

[Craig in Canada]

Would flashpoint be a more reliable base for computing viscosity reduction due to fuel since it isn't also affected by shear? I haven't actually done it, but I'll look into some of your references.

 

[JAG]

I don't see how you could calculate % fuel from Blackstone's flashpoint measurement. That is, if you plotted other people's flashpoint vs % fuel who had over .5% fuel, I think the data would be quite scattered and therefore a linear curve-fit to the data would be not-so useful. I have not done this but I think this just by looking at the data as it comes in. RI_RS4's thread on this subject that's stickied at the top of this forum does have an excellent data set (very little scatter) because the lab used measures these properties differently than Blackstone does.

See what a pain all this curiosity can cause?

That's why I said I wouldn't worry (meaning: pay mind to it) about it since the UOA is so good overall.

 

[Craig in Canada]

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See what a pain all this curiosity can cause?

That's why I said I wouldn't worry (meaning: pay mind to it) about it since the UOA is so good overall.

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Yah, yah, yah...