Had to revive this topic, cause I just got my analysis results in from Blackstone-Labs.com. Looks pretty good according to what they show, for an engine with 11K miles on it (3750 on the oil, which was my first change with Mobil 1)... all the numbers were pretty much at or below the averages except boron and calcium. They don't see any issues, and the flashpoint is still up around 415 degrees, as well as viscosity holding up well. (no antifreeze or water either, and fuel % is .5% - which is great.
I'm looking for extending the intervals, so I did the extra TBN test as well.. all in all it cost me $30 or so, which I don't consider bad considering how interested I am in my engine and how valuable this info could be if I was having problems.
Considering their suggestions, I'm bumping up my change interval around 33% to 5000 miles before the next test. And by this oil test it looks like I've still got life, the old Mobil one is going into the garden tractor - not the recycle bin. I paid for it - might as well use it fully!
They will send you a free test kit if you hit their website -
www.blackstone-labs.com . Read the FAQ also - and print that hazzard letter for the post office to read - they gave me a hard time when I tried to ship it but eventually took it.
Happy testing!
-=RB