I did two oil-sample tests on my 240D and two oil-sample tests on my
190DT, and decided to extend the oil-change interval to 7,500 miles.
(I'm sure I could have gone to 10K miles, but I chickened out.)
Now, I've gone through 2 oil changes on my 190DT and I'll have to do
the 2nd oil change on my 240D in a couple weeks.
Question: is there a reasonable length of time, or number of miles, or
number of oil changes, that I can confidently go before I do more oil
sample tests? (The tests are a little pricey.) What do you think?
Thanks,
Ron Dwelle
