The 3,000 Mile Oil Change 'Myth'

[Sammich]

where the flip is blackstone?

[.blank cd]

where the flip is blackstone?

x74

[scottyb]

where the flip is blackstone?

http://www.blackstone-labs.com/gas_engines.html

there are others, just google "oil analysis."

they tell you exactly what to do and what to expect on their website. i will likely use them on my next oilchange to see if i can take my oil change interval out to 6k or 7k miles.