A basic question I haven't learned the answer after almost 3 years with my Cummins.

 

Soot from the fuel maybe ???

 

Definitely soot

 

my 93 gets black right away, my 03's oil would still look new after 5k miles

 

On both mine, I can change it, start it , shut it down and it's black.

 

I have 4000 on my oil right now and I can read the words on the dipstick thru it. 116,000 miles

 

The same with mine...Maybe it is something to do with the mods we do...More heavier fueling compared to stock..Just a guess...

 

How's that happening? Please tell us your secret.

 

I have a 93 with 170,000 on it. The oil has always been clear even when I change it every 5000 miles you can still see the writing on the dipstick.

 

When I chipped my 24V, I noticed the oil got dark much quicker, as did the last bit of my bed near the exhaust tip.

 

Stock tuned?

What's your secret?

 

Definately the more fuel and also if you just run short trips and not loaded will darken oil faster. And soot is a major factor also.

 

Never have figured this out.....I assume soot

Our 1968 350 John Deere 3 cylinder blackens the oil immediately
Our 1985 JD2550 4cylinder non-turbo blackens the oil immediately
Our 1998 JD6410 4 cylinder turbo blackens the oil a little less slowly despite a bad IP
Our 1993 W250 with 290k blackens the oil in about 3-4000 miles but nowhere near what the tractors do.

I've also heard that its bad if the oil isn't black on a diesel? I don't know what to think. Using rotella t 15w-40 in all of them

 

It's soot from the fuel. How much depends on how clean the burn is and also engine clearances, especially pistons and rings. Diesel rated oils suspend it harmlessly in reasonable amounts, which is pretty black.

 

Another vote for SOOT, like he said. ^^^^^

It also makes a mess when you spill it trying to get it back into the bottle.

Jim