I guess now is as good a time as any to ask about a problem with my car.
Around 1998 I was given a 91 Crown Vic. It is a 302 and had 38,000 miles when I got it. I noticed immediately that there was a tiny bit of white right at the tip of the dip stick.
Now this car belonged to an old lady and after she died, it sat up for a long time but I am not sure how long.
As soon as I got it, I changed oil and filter. I always use full synthetic but no particular brand. Always a name brand tho.
Because I was suspicious of the white stuff, I have always changed the oil and filter at around 2000 miles and never over 3000.
After an oil change, the oil turns dark within 2-300 miles. Also if the engine is cold I still see just a bit of the white stuff at the tip of the dip stick.
The car has around 150,000 miles on it now and the engine still runs great. I still wonder about the oil turning dark so quickly. Also when I drain the oil it is always very dark. This is after only 2000 miles.
What you are probably seeing with black oil is the result of combustion products getting by the rings. Likely the engine never broke in properly when new.
The bit if white is moisture from condensation. Water or coolant mixing with the oil ends up looking a lot like chocolate milk sometimes tinting toward green or red depending on coolant type.
I would just change it according to schedule.
Every time they change the rating letter following the S for gas engines or C for diesels, that is a higher rated oil. Oil today is light years better than what we bought in the ‘60’s.