once it gets to the point where it's black, and from there on out it will black the oil quickly, you can pull the pan and clean out all of the junk in the bottom, and it'll clear right up again. Dunno what the stuff is but it's nasty, it makes a huge mess of your hands, fingers, parts cleaner solution, everything. But it disperses in the engine oil and blacks it up pretty quickly.
Don't know how many times people would bring their stuff in, ask us to change the oil & filter, and then they get it home & call us "you didn't change my oil it's black as tar!".....well it was changed, it just does that sometimes. Give them the option (and cost estimate) to pull the oil pan and clean it and they usually back out.
I took my GAS engined Ram pickup in to Pep Boys in Bedford, TX (when I was working DFW airport I had a crash pad in Bedford) and asked for their el-cheapo oil change. It was a regular exercise for me to let them do it since I wasn’t at my home.) They usually did the job and parked it out on the lot and paged me (I was usually in the store shopping). Almost always was a pleasant experience.
One time tho’ as I paid the bill and walked out to the truck …. I did my usual “pre-flight inspection” after someone else works on my stuff…. I checked that a new filter was installed, and I pulled the dipstick to be certain the correct amount was installed…. and to my surprise the oil was black, not fresh. There was no way that backing it out of the bay and parking it in the parking lot would have dirtied up that oil that quickly.
So I went back inside and told the service mgr that his worker must have gotten distracted or something because the filter was definitely new…but the oil was still the same old stuff I drove in with.
To my shock that young man walked out to my car…pulled the dipstick…looked intently at the black oil on it very closely…. then Wiped it with his finger and TASTED the black oil with his tongue!!!
I let him announce that the oil was indeed ”fresh oil” and tell me that it probably just took-on the color from the residual oil still in the engine.
Rather than get into the discussion further, I thanked him, and drove my car home and did an oil change, and never went back to Pep Boys.
(I now have learned Pep Boys no longer sells parts or accys…. they ONLY perform service work.
They won’t be doing any on my stuff.