Castrol Edge 0W-40, 4650mi, 2003 BMW E46 330i ZHP

[DrivinWest]

I decided to do a UOA on my new to me 2003 E46 330i ZHP. I bought it from the original owner with an impeccable maintenance record.

I was just curious to know if there were any issues that might need to be addressed, as these engines are known to blow head gaskets and drip fuel from injectors when not properly maintained.

 

[FZ1]

Looks really good.

 

[BMWTurboDzl]

I swear something is going on with BS. It seems like viscosity is on the low side for all low mileage UOAs

 

[Artem]

OP: “car has impeccable maintenance history”

Also OP: I’m concerned about potential issues…



Sounds like of all people, you shouldn’t be worried about ANYTHING with this car. Just keep an eye on rubber gaskets and components as the miles rack on. But that’s typical maintenance for any aging vehicle.

 

[CharlesInCharge]

No TBN?

 

[M56959]

Folks if you make a topic, don't get upset if someone posts something you don't like.

If they are not being uncivil or otherwise violating the rules your option is to ignore them.

 

[himemsys]

I swear something is going on with BS. It seems like viscosity is on the low side for all low mileage UOAs

Here's Castrol EDGE 0W40 with 4300 miles with a viscosity nearly that of its virgin value:

Castrol 0W40, 4341 mi, 06 Infiniti M45

Looks like things are clearing up on our M45. Iron and Aluminum are still a little higher than universal averages, but not enough for Blackstone to flag. Everything else is settling down nicely. Previous two oils are M1 0W40 and Supertech 5W30. The oil in there now is M1 5W30 HM SN+. We'll drain...

bobistheoilguy.com

It might have something to do with the previous oil in the vehicle being a lower viscosity and skewing the current oil's viscosity down. If you look at my UOA in link above, previous oil was M1 0W40 with a lower than usual cSt. But the oil previous to the M1 was 5W30. Whereas the Castrol 0W40 looks normal, probably because the previous oil was also 0W40.

 

[edyvw]

Look good, but not really useful without TBN and TAN values.

 

[himemsys]

Look good, but not really useful without TBN and TAN values.

I disagree. Wear metals and mileage on oil plus presence/absence of water, coolant and insolubles are more important than knowing how much further you could’ve gone. If your primary goal is maximizing oil runs, then yes.

 

[edyvw]

I disagree. Wear metals and mileage on oil plus presence/absence of water, coolant and insolubles are more important than knowing how much further you could’ve gone. If your primary goal is maximizing oil runs, then yes.

It is called USED OIL ANALYSIS! Not USED ENGINE ANALYSIS!
Wear metal are specific to engine! UOA is not used for example in testing how oil performs wear wise during development, you actually have to disassemble engine.
So again, UOA is used to get picture of how oil performs. Yes oil can point to an issue, but iron level at 7 or 13 or 17 doesn’t mean anything.

As for coolant etc. fine, you can see what is happening in the engine, but that is not dependent on what oil you use.

 

[himemsys]

It is called USED OIL ANALYSIS! Not USED ENGINE ANALYSIS!
Wear metal are specific to engine! UOA is not used for example in testing how oil performs wear wise during development, you actually have to disassemble engine.
So again, UOA is used to get picture of how oil performs. Yes oil can point to an issue, but iron level at 7 or 13 or 17 doesn’t mean anything.

As for coolant etc. fine, you can see what is happening in the engine, but that is not dependent on what oil you use.

Wear metals mean something when you have universal averages for the same engine type. The far right column on Blackstone's oil analysis. If your engine type averages 10ppm iron over 5000 miles and you get significantly higher or lower per 1000 miles, that is useful to know.

Most, if not all oils today have no problem going 5k miles. If you did a UOA with 5k miles or less, then I see very little point (other than curiosity or if your engine is a fuel dilutor and you want to see how the fuel is impacting the additive package) of getting a TBN.

 

[OVERKILL]

Wear metals mean something when you have universal averages for the same engine type. The far right column on Blackstone's oil analysis. If your engine type averages 10ppm iron over 5000 miles and you get significantly higher or lower per 1000 miles, that is useful to know.

Most, if not all oils today have no problem going 5k miles. If you did a UOA with 5k miles or less, then I see very little point (other than curiosity or if your engine is a fuel dilutor and you want to see how the fuel is impacting the additive package) of getting a TBN.

Edyvw is right though, in that the universal averages are really only useful to give you an idea of what's "typical" for that engine family, but your own equipment may, and most likely will, track differently from that and that's fine, that's why we trend our own equipment. Now, if you see a stark departure, sure, that might warrant some investigation, but that's not what he said, he was talking about small changes in ppm and people reading too much into that, which has a history of happening regularly on here, lol.

Different oils will yield different results too, and that doesn't speak to their wear performance, which can only be determined via tear-down analysis. Chemistries are different, some more aggressive than others, and UOA's have no way to discern between chelation, corrosion and physical wear. So if you have an oil with additives or base oils (like POE) in it that are quite polar, that will typically manifest as higher levels of metals, even though you aren't experiencing higher levels of wear.

 

[edyvw]

They don’t mean anything if you don’t know sample size and if they were used in same exploitative environment. I have Castrol 0W40 yielding better iron numbers after 5k including really harsh track environment than Castrol 0W30 using in winter, no track. So as Overkill said, yes it helps, but keep in mind that “good” wear metals are one of the biggest and costliest mistakes in private aviation. Mechanic says engine needs rebuild, and owner “proves” him wrong with UOA.
In BMW engines it is not TBN that is issue, it is TAN that matters.

 

[himemsys]

Edyvw is right though, in that the universal averages are really only useful to give you an idea of what's "typical" for that engine family, but your own equipment may, and most likely will, track differently from that and that's fine, that's why we trend our own equipment. Now, if you see a stark departure, sure, that might warrant some investigation, but that's not what he said, he was talking about small changes in ppm and people reading too much into that, which has a history of happening regularly on here, lol.

Different oils will yield different results too, and that doesn't speak to their wear performance, which can only be determined via tear-down analysis. Chemistries are different, some more aggressive than others, and UOA's have no way to discern between chelation, corrosion and physical wear. So if you have an oil with additives or base oils (like POE) in it that are quite polar, that will typically manifest as higher levels of metals, even though you aren't experiencing higher levels of wear.

This started with edyvw saying that a UOA is not useful without a TBN and TAN. I simply pointed out that they can be useful and listed the potential ways they could. I'm not going to take it any further than that.

BTW, when you said "Now, if you see a stark departure, sure, that might warrant some investigation", you said basically the same thing as I did when I said, "If your engine type averages 10ppm iron over 5000 miles and you get significantly higher or lower per 1000 miles, that is useful to know." So where is the disagreement?

In BMW engines it is not TBN that is issue, it is TAN that matters.

What specifically is it about a BMW engine that makes TAN useful? I assume you also must test your oil in a virgin state to get a starting TAN value, or the UOA TAN result will be meaningless.

but keep in mind that “good” wear metals are one of the biggest and costliest mistakes in private aviation. Mechanic says engine needs rebuild, and owner “proves” him wrong with UOA.

I get your point that wear metals aren't everything, but all I ever said was that wear metal information can "mean something" and could be "useful to know."

 

[SubieRubyRoo]

This started with edyvw saying that a UOA is not useful without a TBN and TAN. I simply pointed out that they can be useful and listed the potential ways they could. I'm not going to take it any further than that.

BTW, when you said "Now, if you see a stark departure, sure, that might warrant some investigation", you said basically the same thing as I did when I said, "If your engine type averages 10ppm iron over 5000 miles and you get significantly higher or lower per 1000 miles, that is useful to know." So where is the disagreement?


What specifically is it about a BMW engine that makes TAN useful? I assume you also must test your oil in a virgin state to get a starting TAN value, or the UOA TAN result will be meaningless.

I get your point that wear metals aren't everything, but all I ever said was that wear metal information can "mean something" and could be "useful to know."

Used Oil Analysis IS NOT a tool that gives valid insight into what kind and how much wear is going on in an engine. Period. End of story.

Just because you wish a $30 test can give you in-depth insight into a several $k engine does not make it so. Filter debris analysis, ferrography, or actual disassembly & measurement are required to assess actual wear & its source, since UOAs won't even identify anything bigger than like 7 microns. UOAs are only giving you valid data on if that oil stayed in grade and what the TAN & TBN are at the time of the test. That's it.

Overkill tried to teach you something and you disregarded it without even absorbing it. Your "wear metal information can mean something and could be useful to know" are seat-of-your-pants GUESSES at the very best.

 

[himemsys]

@DrivinWest - I apologize for being involved in muddying up your thread. Apparently my simple post disagreeing that your UOA was not useful without TBN and TAN was enough to do that.

@edyvw - I see your point. I hope you also see mine.

@OVERKILL - thanks for the thorough explanation of how different oil chemistries can affect metals without necessarily affecting wear in the same way.

@SubieRubyRoo - FWIW, I am not wishing that a $30 test can give me in-depth insight into a several $k engine. I thought I made that pretty clear. I am teachable, and I did not disregard OVERKILL's information.

 

[Blueshound]

@DrivinWest, just came to give a big thumbs-up for your avatar... Jerry is smiling down on you from Space

 

[edyvw]

This started with edyvw saying that a UOA is not useful without a TBN and TAN. I simply pointed out that they can be useful and listed the potential ways they could. I'm not going to take it any further than that.

BTW, when you said "Now, if you see a stark departure, sure, that might warrant some investigation", you said basically the same thing as I did when I said, "If your engine type averages 10ppm iron over 5000 miles and you get significantly higher or lower per 1000 miles, that is useful to know." So where is the disagreement?


What specifically is it about a BMW engine that makes TAN useful? I assume you also must test your oil in a virgin state to get a starting TAN value, or the UOA TAN result will be meaningless.

I get your point that wear metals aren't everything, but all I ever said was that wear metal information can "mean something" and could be "useful to know."

BMW engines are hard on oil, and oxidation is a problem. BMW has the most stringent oxidation requirements among all factory approvals, for a reason.
The rule of thumb is that if TAN is higher than TBN, oil is done. Now, there might be present very high natural oxidation bcs. base stocks, but BMW does not approve oils like that (an example would be Mobil1 5W40FS).

I get your point, but that is just a very ambiguous comparison that is nice to have. To say UOA is good or bad, cannot be based on those variables. That is my point.

 

[himemsys]

BMW engines are hard on oil, and oxidation is a problem. BMW has the most stringent oxidation requirements among all factory approvals, for a reason.
The rule of thumb is that if TAN is higher than TBN, oil is done.

Interesting. I've only ever heard of used TAN being compared to its virgin value. Does that rule of thumb stand even if you don't know the virgin TAN value?

 

[edyvw]

Interesting. I've only ever heard of used TAN being compared to its virgin value. Does that rule of thumb stand even if you don't know the virgin TAN value?

Pretty much. But some oils generally have higher starting oxidation. I would say it depends on how higher.

Here is my UOA of Castrol 0W30 (righ column, no track) and 0W40 (left column, very harsh track conditions):