2008 BMW M3, BMW TwinPower Turbo 10W-60, 498 mi

[d00df00d]

498 miles on the oil
83368 miles on the engine

Bought this car with just over 80k miles on it and a few thousand left on the most recent oil change. Previous owner had used Shell Helix Ultra Racing 10W-60.

I had the rod bearings changed preventatively (rod bearing wear is a known issue with this engine). At that time, the oil was replaced with BMW TwinPower Turbo 10W-60, which I am continuing to use. The shop advised me that a 500 mile OCI was probably-not-necessary-but-advisable-and-harmless after a rod bearing change, so I did that. This sample is from that OCI.

Not sure where the lead is coming from. Anyone think it could be left over from the old rod bearings? They were lead/copper and rather worn (new ones are apparently aluminum/tin). That was two OCIs ago, though. Man, do I hope it's not from the main bearings...

Pretty sure the fuel dilution was from cold running due to a failing thermostat (just replaced), plus a fair number of short trips.

Copying the numbers here because Polaris's reports are kind of annoying to read:


Iron - 5
Chromium - 0
Nickel - 0
Aluminum - 1
Copper - 0
Lead - 8
Tin - 0
Cadmium - 0
Silver - 0
Vanadium - 0
Silicon - 4
Sodium - 4
Potassium - 1
Titanium - 1
Molybdenum - 54
Antimony - 0
Manganese - 0
Lithium - 0
Boron - 60
Magnesium - 26
Calcium - 2499
Barium - 0
Phosphorus - 861
Zinc - 961

Fuel Dilution - 1.8% (by GC)
Soot - Water -
Viscosity @ 100º C - 18.6
TBN - 7.06
Oxidation - 9
Nitration - 9

 

[RooflessVW]

I don't think 8ppm of lead is indicative of anything without a trend. Is this your first UOA or did you do one before the rod bearing change?

 

[zorobabel]

The engine was taken apart, dust & crap got in, some lead is expected.

 

[d00df00d]

Originally Posted by rooflessVW
I don't think 8ppm of lead is indicative of anything without a trend. Is this your first UOA or did you do one before the rod bearing change?

This was the first UOA on this car.

I know numbers don't mean much without a trend, but I don't think there are many sources of lead in this engine. I'm not aware of any other than the (old) rod brearings.

 

[FlyPenFly]

I think new rod bearings still need to wear in and might be from that? There might be some lead in the new bearings too.

 

[d00df00d]

Originally Posted by FlyPenFly
I think new rod bearings still need to wear in and might be from that? There might be some lead in the new bearings too.

Nope -- the new rod bearings are lead-free.

 

[ammolab]

8ppm lead is nothing. My S54 powered M Coupe got new rod bearings when the lead hit 68ppm @ 60,000 miles...and NEEDED them for sure.

 

[d00df00d]

Significant correction: if the lead in this sample had come from the previous rod bearings, that would have been from one OCI ago, not two. Derp. Wish I could edit the OP.

Also forgot to list the particle quantifier (PQ) index of 11.

Anyway....

Assuming that all the lead came from the old rod bearings, that there is no other source of lead in this engine, and that around 10% of the oil system's total capacity was left in the engine, cooler, and plumbing after everything was drained for the rod bearing service... wouldn't that mean the previous oil would have had a lead count in the neighborhood of 80 ppm? I know those are slightly sketchy assumptions; I just want a check on the math.

 

[Artem]

I think another 500 mile sample is needed for comparison. Don't drain the sump, just sample.

Who knows where it's from but the next UOA will surely help tell the trend.

 

[Gokhan]

Don't they have other brands of 10W-60? Perhaps, try Amsoil. High lead could be because of some peculiar chemical effect of Castrol 10W-60.

 

[d00df00d]

Just spoke with Polaris about the aforementioned lead number math. Basically, the answer is no; too many variables to say for sure.

Repeating this to be clear: the only reason I'm attending to this 8 ppm lead number is that I'm not aware of any other sources of lead in this engine. So, if there's ANY lead at all in this report, it's residual and/or it means there's something I don't know about this engine.


Originally Posted by Artem
I think another 500 mile sample is needed for comparison. Don't drain the sump, just sample.

Good call. Would be nice. Not easy with this engine, unfortunately. There's no dipstick so pulling a sample would necessarily involve draining a few liters of >$10/L oil. Considered a Fumoto valve or something similar, but I don't like the implications for ground clearance...


Originally Posted by Gokhan
Don't they have other brands of 10W-60? Perhaps, try Amsoil. High lead could be because of some peculiar chemical effect of Castrol 10W-60.

Yes, there absolutely are other 10W-60s. I'm really not inclined to mess around with oil in this engine, though. My policy is not to stray from OE unless there's a VERY clear and well-demonstrated reason that applies to my specific case, and there's been no such thing for non-spec oil for this car (surprise, surprise).

BMW switched from Castrol to Shell a while back, so TwinPower Turbo 10W-60 is a Shell product. AFAIK high lead isn't a thing for either this oil or the Castrol product.

 

[Gokhan]

Originally Posted by d00df00d
Originally Posted by Gokhan
Don't they have other brands of 10W-60? Perhaps, try Amsoil. High lead could be because of some peculiar chemical effect of Castrol 10W-60.
Yes, there absolutely are other 10W-60s. I'm really not inclined to mess around with oil in this engine, though. My policy is not to stray from OE unless there's a VERY clear and well-demonstrated reason that applies to my specific case, and there's been no such thing for non-spec oil for this car (surprise, surprise).BMW switched from Castrol to Shell a while back, so TwinPower Turbo 10W-60 is a Shell product. AFAIK high lead isn't a thing for either this oil or the Castrol product.

Ah, so, it' Shell.