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08-12-2026LAST POST
My oil analysis at 30k miles (47km).
A little concerning... Inviting insight...
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Quick question, I have not been able to put 7500 miles in a calendar year. Should I still change the oil?
13Ghost wrote
My oil analysis at 30k miles (47km).
A little concerning... Inviting insight...
Do you have any previous reports, or is this your first? Looks like your first but I wanted to make sure. Aluminum and tin appearing together does seem problematic but it's impossible to say anything meaningful without a prior history.

How is the car driven?
First analysis.

I'm the second owner and acquired it at the beginning of summer.
Low miles and a complete service history. Difficult to say how it was driven prior but used as a daily summer commuter now.

My intention is to change the oil at the stealership today to satisfy the very limited 3rd party warranty I have.

I was going to take the car off the road in a month, but by the time It would be on the road again, the warranty period would run out. Sounds like unless the part fails the warranty won't cover failing bearings but will call and confirm with them.

Just wished I had more similar analysis to compare to and the results of those cars. Maybe I'm concerned over nothing?
13Ghost wrote
First analysis.

I'm the second owner and acquired it at the beginning of summer.
Low miles and a complete service history. Difficult to say how it was driven prior but used as a daily summer commuter now.

My intention is to change the oil at the stealership today to satisfy the very limited 3rd party warranty I have.

I was going to take the car off the road in a month, but by the time It would be on the road again, the warranty period would run out. Sounds like unless the part fails the warranty won't cover failing bearings but will call and confirm with them.

Just wished I had more similar analysis to compare to and the results of those cars. Maybe I'm concerned over nothing?
Even if you did have reports from other cars to compare to, it's unclear what conclusions you could draw because each engine has its own wear profile even controlling for mileage etc.

Some options from here (not mutually exclusive):

1. Continue sampling at short intervals, as Blackstone recommends
2. Switch to something like Polaris Labs's "Advanced Engine Plus" service, which includes a PQ index (additional measure of iron wear for an extra data point, not much more money)
3. Pony up for much more expensive testing on your oil and filter (call Polaris or maybe some other labs and see what they advise)
Thanks. I appreciate it.

I intended to send this sample to another lab (likely Polaris) and see if it's consistent with blackstone's report since the sample will be from the same oil at a very short interval.

I know oil analysis are a much debated topic, but a little insight might help save an engine ... or lighten the wallet unnecessarily. Lol
Happy to help.

This isn't on you; just a rant about how oil analysis has been popularized. It's so oversold, and... mis-sold? Is that a word? It's talked about like one report can tell you everything you need to know about wear, which is completely false and possibly misleading in almost all cases.

It can be good for tracking wear if there's a likely failure mode that shows up in a clear way on oil analysis, or if you have perfect knowledge of the engine's metallurgy and oil's chemistry. And even then, you still need a history of samples at regular and short intervals, or you can't be sure what you're looking at. We definitely have the likely failure mode piece, but we don't know how reliably it shows up on oil analysis for any bearing other than the original BMW ones -- and even there it's sketchy because there have been engines with worn bearings but clean oil analysis reports; in other words, false-positives are rare enough but false-negatives aren't.

Beyond that, we have squat. Almost no one outside of BMW, Castrol, and Shell has anywhere near the required info on the engine's metallurgy and oil chemistry, and none of those parties will be sharing what they know any time soon. The manufacturers of aftermarket bearings will of course know the alloys they're working with, but you can bet everything you own that they haven't done a fraction of the necessary testing to figure out whether and how wear on their bearings shows up on oil analysis in this engine.

It's possible that other rod bearings (aftermarket and LCI) will show wear in a predictable way on oil analysis. Glyco, the manufacturer of the LCI bearings, advised me to look for Al and Sn trending upward in a (very) roughly 9:1 ratio. What we don't yet know are the false-positive and false-negative rates.

There are more expensive forms of oil analysis that go into FAR more detail about what exactly is in your oil. Those technically still require the aforementioned knowledge of metallurgy and chemistry, plus trending, to be truly meaningful. But in a pinch, a one-off of those methods is at least a step up from a one-off garden variety $20-$30 analysis.

In consumer car engines, what garden-variety oil analysis is really useful for tracking is:

1. Contamination, and
2. How the oil itself is holding up.

This includes the "wear" numbers because they can go high from acid buildup or highly active surface chemistry. So, if you want to see whether you're running your oil too long, or if your filters suck, or if your engine isn't running quite right, etc., oil analysis can be a good tool.

FWIW, I had LCI rod bearings put in shortly after I bought my car, and I'm doing oil analysis at every oil change. My thinking is that if I start seeing that 9:1 Al:Sn ratio, I'll plan for another rod bearing change then. But if not, I'll still plan to revisit the bearings after 60k-80k miles -- unless it becomes clear by then that clean reports reliably indicate low/no wear on these bearings.
2008 6MT (702/703 rod bearings)
4945 miles on the oil (BMW TwinPower Turbo 10W-60)
95449 miles on the engine

Follow-up from this.

Two road trips, a few blasts at the Tail of the Dragon, one tank of no-name non-ethanol gas, and one Techron treatment on this run. Also caught and fixed a pre-cat exhaust leak on one bank near the end, so there's probably some sub-optimal running as well (might explain the fuel dilution).

No idea where the silicon has come from. Maybe the VC gasket change I did just before this oil went in?

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


Iron - 7
Chromium - 0
Nickel - 0
Aluminum - 2
Copper - 2
Lead - 0
Tin - 0
Cadmium - 0
Silver - 0
Vanadium - 0
Silicon - 23
Sodium - 2
Potassium - 1
Titanium - 0
Molybdenum - 49
Antimony - 0
Manganese - 0
Lithium - 0
Boron - 52
Magnesium - 30
Calcium - 2490
Barium - 0
Phosphorus - 840
Zinc - 957

Fuel Dilution - 1.8% (GC)
Soot - <0.1% by vol.
Water - <0.1% by vol. (FTIR)

Viscosity @ 100º C - 18.3 cSt
TBN - 5.26
Oxidation - 11
Nitration - 10

Particle Quantifier (PQ) Index - 12
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I just got the latest analysis for my 08 on original bearings. BMW 10w60
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Uploading my most recent Blackstone analysis (~88.5k, original owner) for anyone who wants to take a look.

Also, adding a DCT fluid analysis at 71k I never got around to uploading.
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Webz wrote
Uploading my most recent Blackstone analysis (~88.5k, original owner) for anyone who wants to take a look.

Also, adding a DCT fluid analysis at 71k I never got around to uploading.
The PDFs have your personal information in them. You should remove them and take a screenshot instead so you can edit it easier.
nydog wrote
I just got the latest analysis for my 08 on original bearings. BMW 10w60
Trending well. Keep doing what you're doing.



Webz wrote
Uploading my most recent Blackstone analysis (~88.5k, original owner) for anyone who wants to take a look.

Also, adding a DCT fluid analysis at 71k I never got around to uploading.
Looks pretty good. I think your change interval is spot-on.
Almost at 170k factory bearings
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Unreadable
330indy wrote
Unreadable
Fixed :thumbsup:
2008 6MT (702/703 rod bearings)
4812 miles on the oil (BMW TwinPower Turbo 10W-60)
100,261 miles on the engine/car

Follow-up from this.

A little more than halfway through this OCI, my car threw a code for a precat O2 sensor. As I understand, O2 sensors typically fail gradually, so I'm assuming this one -- and thus the engine -- had been running sub-optimally for some time before now. I'm also assuming the other O2 sensor wasn't far behind. Maybe that partly explains my historically high fuel dilution numbers. Hoping so. Replaced both about 2k miles before the drain and the car ran noticeably better.

Also ran a bottle of Techron in the fuel tank about 1000 miles before the drain.

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


Iron - 8
Chromium - 0
Nickel - 0
Aluminum - 2
Copper - 2
Lead - 0
Tin - 0
Cadmium - 0
Silver - 0
Vanadium - 0
Silicon - 13
Sodium - 3
Potassium - 2
Titanium - 0
Molybdenum - 49
Antimony - 1
Manganese - 0
Lithium - 0
Boron - 47
Magnesium - 30
Calcium - 2365
Barium - 0
Phosphorus - 735
Zinc - 920

Fuel Dilution - 1.8% (GC)
Soot - <0.1% by vol.
Water - <0.1% by vol. (FTIR)

Viscosity @ 100º C - 17.7 cSt
TBN - 4.19
Oxidation - 12
Nitration - 10

Particle Quantifier (PQ) Index - 12
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Got first report of my ownership. The previous owner did get the RB replaced but no oil analysis.
In general, the report looks solid, the new BE RB has about 40+ K miles and seems ok.

However, the universal average seems to be 2011-2013 MY, but my car is actually Jan 09 car/engine. It should not be too far off I hope.
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Bought the car 11/19 with ~74.8k on the clock, AFAIK it's on the original RBs.

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Assimilator1 wrote
Bought the car 11/19 with ~74.8k on the clock, AFAIK it's on the original RBs.
Looks good mate , keep it this way ! :thumbsup:
I plan to ;), I'll probably end up changing the RBs next year anyway, lol. The report is a stop gap measure whilst I look into all this.
e92zero, leo95se, MTROIS or anyone whose done regular oil analysis, have you got oil reports from the 1st service? (including running in service would be ideal).
4corners wrote
I had my oil analyzed every oil change for over 100,000 miles and it did not detect the condition of my bearings. In fact glowing reports. I don't think it's worth the trouble. I changed my bearings at 147800 miles and they will be changed every 60-70,000 miles from now on if I still own the car. No more oil analysis.

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Old post I know, but are the oil reports you mention shown in this thread? (or somewhere?)
2008 6MT (702/703 rod bearings)
4915 miles on the oil (BMW TwinPower Turbo 10W-60)
105,176 miles on the engine/car

Follow-up from this.

In the 20k miles prior to this OCI, I caught and fixed at least 3 possible causes of fuel dilution: failed coolant thermostat, a precat exhaust leak, and a precat O2 sensor failure. Each time I hoped the fuel dilution would come down. Maybe it finally happened, if only slightly.

Nothing else of note in this OCI.

Copying the numbers here because I don't like how Polaris's reports are formatted:


Wear Metals
Iron - 6
Chromium - 0
Nickel - 0
Aluminum - 3
Copper - 2
Lead - 0
Tin - 0
Cadmium - 0
Silver - 0
Vanadium - 0

Particle Quantifier (PQ) Index - 13


Contaminant Metals
Silicon - 7
Sodium - 10
Potassium - 0


Multi-Source Metals
Titanium - 0
Molybdenum - 44
Antimony - 0
Manganese - 0
Lithium - 0
Boron - 49


Additive Metals
Magnesium - 21
Calcium - 2249
Barium - 0
Phosphorus - 716
Zinc - 828


Other Contaminants
Fuel Dilution - 1.5% (GC)
Soot - <0.1% by vol.
Water - <0.1% by vol. (FTIR)


Fluid Properties
Viscosity @ 100º C - 17.6 cSt
TBN - 4.31
Oxidation - 11
Nitration - 10
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