'02 BMW 530i, GC 0w-30, 6137 miles

[Quattro Pete]

This is my second UOA on this engine. Right now the car has 49k miles.

When I took the sample, oil had about 5 months of use on it. A mix of hwy and city driving in south Florida plus a 1400-mile trip from Miami to Chicago.

Previous sample shown here (10/14/2007) was with GC (gold) 0w-30 as well.

Not sure what is up with that glycol, but it's significantly down this time, however both fuel and TAN are up.

Comments? Questions?

 

[02zx9r]

i cant see it at work but will check it out at home and give my thoughts

 

[JAG]

I keep seeing high TAN in Dyson reports. I wonder what the virgin oil TAN would have tested at. Without that it makes it hard to know when it's truly too high. If we follow one sometimes used criteria, that when TAN = TBN it's time for an oil change, this oil was shot. But it's only 6100 miles on GC in a large sump BMW that is spec'd to be able to go 15K miles on the right oils (GC being one of them). So what's the deal?

A more common condemnation criteria here and elsewhere is to ignore TAN and say the oil is shot when TBN is less than some value: 1 or 2 or whatever, depending on the TBN test method and how low you will let it go. I don't like that method either because is can give false positives (oil is truly shot in some way, maybe ability to maintain cleanliness or it is acidic enough to dissolve soft metals).

 

[Quattro Pete]

I forgot to mention, I was using LC during this interval: 12 oz at oil fill, and then 2 oz every 1k miles.