Well this is a first for me.

[crashz]

My latest group of diesels (2017 Kubota 2501, 2003 F450 7.3L) run for some time before getting dirty. The oil in the Ford is still amber color, and you can still see the metal on the dipstick through it. Dirtier than new but very clean for a year in a diesel. Kubota is the same, but gets black at the ~50-70 hr mark.

Clean, tight engines? Non- emissions garbage? Don't know.

 

[aczlan]

Oh c'mon, tell us what oil you put in 'er! Don't be shy, lol.

But another thought: The instant "blackness" of new oil in diesel engines can also be affected by how thoroughly you drain the old stuff out. IE, one half cup of residual sooty black oil left in the filter housing, pan, or block can make a fresh gallon of new oil look dirty right away once mixed back in. If your machine has a well designed oil system and you drained it out on a 120 degree day (YUCK, btw), I bet it drained very well and you got all the old thin junk out.

Back when I worked doing lawn care (and was assigned to the shop when needed for oil changes and blade sharpening) my boss had us put the plug back into the engine after it drained, put in a little oil (a cup or two), then drain it out.
If it was a walk behind mower or other small piece of equipment, I would "swish" it around a little first.
That way all the dirty oil came out and the new oil stayed cleaner a little bit longer.

Aaron Z

 

[Oldpath05]

I just unplug and drain then re-plug, what stays stays til next time. I accidently went over 6k miles and 10 month on my Jeep with GTX 5/30 oil this summer, it was thin and black, probably the motor said thanks and about time or maybe the Purolator oil filter said, ah dont worry about the mileage I'm good for it.
https://shop.advanceautoparts.com/p...6-P?navigationPath=L1*14926|L2*14960|L3*15110

 

[rScotty]

It is all carbon black soot, that a bypass filter can remove, I run a 3 micron on my 7.3L ford and long drives will clean the oil back to clear after short runs dirty it.

Bypass filtration is the simplest & most effective trick in the book. That's all it takes to make an engine last twice as long.
rScotty

 

[RalphVa]

Normally after any diesel oil change the new fresh oil I put in is instantly BLACK even when I just check the oil
for the proper amount while refilling the engine.

Last week I changed the oil min, my Excavator, after seeing the very thin viscosity oil the dealer had in the unit when I purchased it used. I replaced their oil with my favorite 15/40 oil mostly because of the temps here( been 117 - 122 all weel). Anyway, after running the machine for 10 hours in brutal conditions, I checked the oil and to my surprise, the oil was about as clean as when I put it it in. I did the old rub it between my finger "test" for viscosity and it was nice and thick unlike what I replaced which was as thin as hydraulic fluid.

Like I said that's a first for me not seeing JET BLACK engine oil in a diesel. I don't know is it the Yanmar technology in the TB260, because my Mercedes Sprinter ALWAYS had black as coal looking oil even after a change. Same with Ford GM, Hino, etc.

View attachment 664948

The Isuzu diesel on the generator is like that. Oil stayed mostly clean through the first 50 hours. Starting to get a tad dark now with around 200 hours on this oil change.

Ralph