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.
Thanks. It is not using much if at all tho it has a leak right at the back of the engine on the drivers side. I have tightened it a couple of times but I guess I can live with it.
The plugs do not seem to have any buildup. The last time I changed them I had to leave one because it was so hard to get to. I keep thinking I will get to it but have been ill for a long time and am just now getting better. The plugs are really difficult. The really bad one is the second one from the back on the passenger side.
I have been extremely lucky about finding full synthetic on clearance. I have paid as little as a dollar a quart.
Yep the white often gathers in the dipstick tube.