Oil Analysis Reports

[Assimilator1]

nowayout Hmm, yea that's not great.
And bearing in mind that nearly all the earlier (lead/copper) bearings pulled come out significantly or severely worn (gone through the protective lead layer to copper), I'd be pulling those bearings out if I were you.

I did the bearings in my own car (a 2008 car), inspite of very low lead and copper numbers in an OA, all my old top bearings had worn through to copper!
Btw, you might be interested in the 1st link in my sig, re oil analysis and bearings.

[S65Hunter]

Howd I do?

[a5m]

Originally Posted by S65Hunter

Howd I do?

What bearings are you running? Any track time? That viscosity sheared like ass. On a similar OCI mine on Red Line 5W50 was at 18.8 cSt.

Your copper, tin and lead numbers look good. Mine were higher at 7, 3 and 1, respectively.

[img]"]https://bobistheoilguy.com/forums/attachments/1734224790476-7d9cd6ff-40da-4ec8-8714-17bb90c54bbe_1-3-webp.254191/[/img]

[S65Hunter]

Originally Posted by a5m

What bearing are you running? Any track time? That viscosity sheared like ass. On a similar OCI mine on Red Line 5W50 was at 18.8 cSt.

Your copper, tin and lead numbers look good. Mine were higher at 7, 3 and 1, respectively.

[img]"]https://bobistheoilguy.com/forums/attachments/1734224790476-7d9cd6ff-40da-4ec8-8714-17bb90c54bbe_1-3-webp.254191/[/img]

The PO had the bearings replaced by BMW do its their "updated" bearings. No track time, it's just a weekend car. Though I drive it very hard every time I drive it. Not sure if this Texas summer heat has anything to do with that. I've been considering replacing the RBs with a better alternative as well

[a5m]

Originally Posted by S65Hunter

The PO had the bearings replaced by BMW do its their "updated" bearings. No track time, it's just a weekend car. Though I drive it very hard every time I drive it. Not sure if this Texas summer heat has anything to do with that. I've been considering replacing the RBs with a better alternative as well

Definitely the heat will have an affect. Red Line is generally known to be more robust in terms of shear resistance and viscosity.

Forgot to mention, I'm on BE v2 bearings. That above OCI was after they were changed, so maybe some leftover there from the original bearings, which were worn but perfectly fine.

I'd just go with BE for the peace of mind. Especially if you're driving it hard a lot (which is good ).

[S65Hunter]

I may try and get deansbimmer to chime in. If i were to replace the RB's, thats who would be doing it since hes just 30min away. That, and thats the only shop I trust with my car.

[IamFODI]

Originally Posted by S65Hunter

Howd I do?

My conclusion would be that your fuel dilution is much higher than the "fuel dilution" reading suggests. I've seen this a lot with Blackstone reports – they show zero fuel dilution when the viscosity and/or flash point say otherwise. In your case, it shows more than zero, so I suspect the actual number is higher – especially given how low the viscosity is. That might also explain the slightly elevated iron wear.

For street use to come anywhere near track use in terms of wear potential, you'd have to be abusing the hell out of your engine. Burnouts, donuts, launching and redlining the first two gears at every traffic light, free-revving to redline, going too hard when the oil is cold, etc. High throttle and RPM at low speed, a lot. If you were to drive fast enough on the street to mimic track use in this car, you'd get arrested or killed long before your engine wore out.

Re. rod bearings: how long has it been since the PO replaced them?

[S65Hunter]

Originally Posted by IamFODI

My conclusion would be that your fuel dilution is much higher than the "fuel dilution" reading suggests. I've seen this a lot with Blackstone reports – they show zero fuel dilution when the viscosity and/or flash point say otherwise. In your case, it shows more than zero, so I suspect the actual number is higher – especially given how low the viscosity is. That might also explain the slightly elevated iron wear.

For street use to come anywhere near track use in terms of wear potential, you'd have to be abusing the hell out of your engine. Burnouts, donuts, launching and redlining the first two gears at every traffic light, free-revving to redline, going too hard when the oil is cold, etc. High throttle and RPM at low speed, a lot. Fast street driving alone will probably kill you or get you arrested and your car impounded before the car wakes up.

Re. rod bearings: how long has it been since the PO replaced them?

Yeah im definitely not THAT hard on the car. But it very frequently see red line typically 2nd-4th. And I always wait til the oil is about 200F before driving that way. RB have just about 20K miles on them.

[IamFODI]

Originally Posted by S65Hunter

Yeah im definitely not THAT hard on the car. But it very frequently see red line typically 2nd-4th. And I always wait til the oil is about 200F before driving that way. RB have just about 20K miles on them.

Got it. In that case:

1. Sounds like you're operating well within what this engine was designed to take in terms of mechanical stress. Track use is ~4k to redline, mostly WOT, nonstop, and this engine was made to take that for very long periods of time even in hot weather.

2. Given that, I'm even more confident saying you need a second opinion on fuel dilution, because the only other explanation is that Motul 10W-60 just can't hang. I use Polaris Labs, and one reason is that they test fuel dilution by a different method that's much more trustworthy IMO.

3. For your rod bearings, the only thing I'd be worried about is install error, but 20k miles is enough that you're probably safe from that. The updated BMW bearings are fine, at least when used with BMW bolts. They had some failures early on, but the discoloration people assumed was wear is actually superficial and we have yet to see a single set that shows actual wear like what we saw with the original bearings. Down the line, feel free to replace them with something else if you really want to, but zero hurry to do so now.

To be clear, I do think you have a problem: that viscosity loss is awful. I'd be surprised if it didn't cause excess wear. I'd want to diagnose and fix it ASAP. I've done a few track events and had fuel dilution up to 2.6%, and I've never seen viscosity that low with BMW 10W-60, especially after they switched back to Castrol from Shell.

[S65Hunter]

Originally Posted by IamFODI

Got it. In that case:

1. Sounds like you're operating well within what this engine was designed to take in terms of mechanical stress. Track use is ~4k to redline, mostly WOT, nonstop, and this engine was made to take that for very long periods of time even it hot weather.

2. Given that, I'm even more confident saying you need a second opinion on fuel dilution, because the only other explanation is that Motul 10W-60 just can't hang. I use Polaris Labs, and one reason is that they test fuel dilution by a different method that's much more trustworthy IMO.

3. For your rod bearings, the only thing I'd be worried about is install error, but 20k miles is enough that you're probably safe from that. The updated BMW bearings are fine, at least when used with BMW bolts. They had some failures early on, but the discoloration people assumed was wear is actually superficial and we have yet to see a single set that shows actual wear like what we saw with the original bearings. Down the line, feel free to replace them with something else if you really want to, but zero hurry to do so now.

To be clear, I do think you have a problem: that viscosity loss is awful. I'd be surprised if it didn't cause excess wear. I'd want to diagnose and fix it ASAP. I've done a few track events and had fuel dilution up to 2.6%, and I've never seen viscosity that low with BMW 10W-60, especially after they switched back to Castrol from Shell.

I wonder if excessive idling could contribute to the viscosity loss. That could be a factor in my situation. So I'll hold off on letting the car warm up as long as I tend to do and just start it up, let idle settle and then drive normally until the oil is at temp.

[spammysammich]

There is lots of anecdotal evidence of leaking injectors on this platform

[IamFODI]

Originally Posted by S65Hunter

I wonder if excessive idling could contribute to the viscosity loss. That could be a factor in my situation.

Oh wow. Yes, absolutely.

Originally Posted by S65Hunter

So I'll hold off on letting the car warm up as long as I tend to do and just start it up, let idle settle and then drive normally until the oil is at temp.

Exactly. This is what to do.

[S65Hunter]

Originally Posted by IamFODI

Exactly. This is what to do.

Since I just changed my oil (less than 200 miles ago) I won't let it idle and warm up prot to driving. Then next oil change i may send another test out and see what the results are.

[a5m]

Originally Posted by S65Hunter

Since I just changed my oil (less than 200 miles ago) I won't let it idle and warm up prot to driving. Then next oil change i may send another test out and see what the results are.

I'd do OAI or Polaris as mentioned for the UOA. They can do a GC and get the actual fuel dilution.

[Assimilator1]

Talking of OA.
For my car, oil was 2 years old, mileage in report. Did 4 track days on it.
I was surprised that soot was at 0 seeing as how dark the oil came out!
Had to ask for the 40C testing .
PaulGros Got TAN done too seeing as you thought it'd be useful .

New oil specs as per 2021 datasheet:-
Kinematic viscosity @100C 23.1 cSt
@40C 160.1 cSt
Density @15C g/ml 0.8458

So if I've got this right, my oil has sheared down to the upper end of the 50 grade @100C.
But I can't work out what the equivalent grade is for the cold end at 40C w rating using the viscosity grade table I have. Can anyone else?

[Assimilator1]

Originally Posted by S65Hunter

Howd I do?

Seeing as your oil is also 10w60, I don't get why they say it should be between 15.5-22.9 at 100C as that corresponds to 40 to 60 grades!
60 grade is from 21.9-26.1 @100C (going by the attached doc).

[IamFODI]

Originally Posted by Assimilator1

But I can't work out what the equivalent grade is for the cold end at 40C w rating using the viscosity grade table I have. Can anyone else?

W ratings are based on cranking and pumpability – so, medium-to-high shear rates – at much colder temps than 40º C.

The viscosity measurements you got are of kinematic viscosity, which is a low-shear condition (basically how quickly gravity pulls it through a hole of a given size).

Kinematic viscosity at 40º C doesn't figure into SAE viscosity grades.

[Assimilator1]

Originally Posted by IamFODI

W ratings are based on pumpability – so, medium-to-high shear rates – at much colder temps than 40º C.

The viscosity measurements you got are of kinematic viscosity, which is a low-shear condition (basically how quickly gravity pulls it through a hole of a given size).

Kinematic viscosity at 40º C doesn't figure into SAE viscosity grades.

Got ya, I was beginning to wonder that.
So the best we can do is compare this lukewarm 40C kin viscosity figure to the manufacturers figure? (where tested).
It seems that OA doesn't test the cold pumpabilty property? (At least mine and the previous one didn't). Is that typical for OA?

So my oil has sheared down thinner at 100C (as expected) to somewhere around 50 grade, and has also got thinner at 40C. The latter was not something I was expecting, my understanding is that as multigrade oil wears/shears down that the grade range shrinks, so it gets thinner at the hot end and thicker at the cold end. Is it because 40C simply isn't cold enough to show that? Or am I missing something?

[IamFODI]

Originally Posted by Assimilator1

So the best we can do is compare this lukewarm 40C kin viscosity figure to the manufacturers figure? (where tested).

Yep. Not aware why that'd be useful, but I'd be curious.

Originally Posted by Assimilator1

It seems that OA doesn't test the cold pumpabilty property? (At least mine and the previous one didn't). Is that typical for OA?

Yep.

Originally Posted by Assimilator1

So my oil has sheared down thinner at 100C (as expected) to somewhere around 50 grade, and has also got thinner at 40C. The latter was not something I was expecting, my understanding is that as multigrade oil wears/shears down that the grade range shrinks, so it gets thinner at the hot end and thicker at the cold end. Is it because 40C simply isn't cold enough to show that? Or am I missing something?

Not the "grade range" necessarily, but the viscosity index – a number mostly independent of the grade that indicates how much viscosity changes with temp (higher VI = less viscosity change).

AFAIK, there are two main modes of viscosity loss: additive breakdown and fuel dilution. The main mode of viscosity increase is oxidative thickening. You might be seeing any combination of those.

Additive breakdown stems from the fact that multigrade oils tend to be made by mixing lower viscosity base oils with viscosity index improvers (VIIs) that help the mixture retain more of its viscosity as temps increase. Some VIIs can break down permanently in service, causing viscosity loss over time. That viscosity loss will show up mostly at high temps, though it might also show up a little at low temps depending on the base oils and VIIs used. VII breakdown is less of an issue now than ever; we have better VIIs now, as well as better base oils that have better VIs to start with and thus need less VII to meet targets. A lot of Internet wisdom echoes old thinking and thus overstates the problem. But it's still a thing sometimes, especially for grades with big "spreads" like 0W-40 or 10W-60 (those aren't really "spreads" because the numbers are defined by different kinds of measurements, but I don't know a better word).

Fuel dilution is pretty straightforward and would affect the oil at most or all temps.

Unfortunately, I don't know if or how oxidative thickening shows up differently at various temps. Am I seeing correctly that your oil wasn't tested for oxidation?

Incidentally, oxidation might explain why your oil seemed dark.

[Assimilator1]

Interesting stuff, and it makes sense now, thanks.

Yea, no oxidation test, neither has the previous posted here by S65Hunter, can't say I remember seeing it on other OAs? Is it routinely tested?

[IamFODI]

Originally Posted by Assimilator1

Yea no oxidation test, neither has the previous posted here by S65Hunter, can't say I remember seeing it on other OAs? Is it routinely tested?

Basic test packages usually don't include it. I've been using Polaris Labs's Advanced Engine Plus package and it includes oxidation.

[Impastokitsch]

not sure if u guys tried this PAO 10W60 before but i did and the result seems good?! I am on BE BEARING too but 2 years old.