The oil filter looked fine, and the oil looked clean. I've seen much worse on dino oil and shorter intervals. I suppose we should find a way to test the filters too..... But the results above aren't showing that much floating around in the oil.

Nik

 

I figured it did Nik. Generally an engineer would design a system from beginning to end and not skip something like a filter. There have been those that say the filter is not up to task, but if it wasn't the oil would show it. Thanks for posting this, it goes with what I have been saying for years.

 

Hey gang.
Hate to gooseberry here, but TBN without TAN is still incomplete. I worked for years at an industrial fluids manufacturer and formulated many fully synthetic engine oils. While a decent TBN is good, without the TAN you might be misled. TAN, for those not familiar, is the Total Acid Number. While TBN is a measure of acidic combustion buffering ability, TAN is how much acidic components have already been absorbed. If TAN is excessive, you have basically acid flowing in metallic containment. Acid dissolves metals, so I tend to focus on the TAN rather than the TBN.
As a side note, I personally ran a long drain interval test on one of the oils I formulated, fully synthetic, in my 280zx. For my test, which hit around 17k miles before shutdown, TAN was the failure criterion while everything else looked good. Just like your test shown above...
Just sayin'... Your milage may vary, but I would hate to read about your test going south on a missing data point.
Cheers
Robert

 

Are you sure there? From Blackstone labs "Scientifically speaking, the TBN is one of two "neutralization number" tests run on oils. The TAN (total acid number), which is used for hydraulic oils, is the other. The TBN measures the total basedity of an engine oil; that is, how much base (as in, a base vs. an acid) additive is in the oil to offset the deleterious effects of acids coming into the oil from combustion and other sources."

Nik

 

TBN and TAN are important, but even by your own statement above, if you follow the 15K mile change as MINI suggests, you should be within tolerances of the oil's ability.

My point is that the 5K oil change is bunk and that synthetic oil can go much further. I do think that 20K is pushing it though.

 

Actually that's a good point. And for full disclosure, I never run my oil beyond 7500 in any vehicle I drive, fully synthetic of course! The 17k test was the first and last time I extended my drain interval, and even then I pulled samples every 1000 for testing. I'd NEVER run long like that blind!


And yes I'm quite sure TAN is used for engine oils, just check ASTM D664 and D974. The test is useful to determine life left for many oils, not just hydraulic...

 

Been running 15K intervals for over 6 years now without a single problem. I had samples pulled in Germany at 15K with TBN and TAN and all was good. I see no reason not to follow the manufactures intervals.

 

me too bro! never beyond 7500 for my MINI. And I only use the full synthetic German made oil. Castrol 0W-30 or BMW 5W-30. (That way you know it really is full syn).

 

Great story bro!

 

Well, it's time for an update on my oil analysis. Currently the milage on the car is a little over 321,000 miles, and I guess the engineers at BMW were wrong in their calculation on when oil needs to be changed. Apparently I am chaining mine to often.

Nik

 

Another one....

 

Great results for that kind of OCI.

341k!!! Wow! that's only 275k more than mine.