What makes our oil black anyways?

[yARIC008]

I'm just wondering why our oil turns black so quickly. I have no detectable blow by, engine is almost new, but even since day one, the oil was completely black in a day or two...

Our 6L has about 1,500 miles on it and the oil still looks brand new?

***:

 

[argve]

I don't know why it would happen slower on your new truck but I know that the detergents in motor oils turn black after being heated. It could also be because the detergents are picking up some soot that is getting into the engine or some that was left over from previously from the componets that were reused... (oil cooler and such).

Don't really know but that is my 2 cents...

 

[budtoh3zo]

How i under stand it is the 6.9L makes alot more soot then the new once and the soot gets in the oil. I noticed that to between mine and dads. People say if you run Bio diesel the oil stays clean longer of if you run propaine all the time. I can see it because the IDI do put out alot of soot

 

[towcat]

I believe this is where the marvels of computers come into play. On our older motors, we have a larger "fudge" factor in our feul delivery and consumption. With no turbo, our best efficency is 75%. That means there is 25% of the feul is washed down the cylinderwalls or out the tailpipe. With a turbo, we do have improved efficency but the fine tuning is still restricted by the injection pump and our foot. With the newer trucks, feul economy and emissions is the larger concern, so the computer is constantly tweaking on the injectors to keep things "efficient" the somewhat intended by-product is added power. so, you ask why is our basement motor's oil is so "dark" compared to the new "darkside" brothers? Its in the computer, not the sum of the parts. BTW, this is condensed from a conversation at INO burgers with a darkside jockey who works as an engineer for Cummins. Crazy huh?

 

[F350camper]

Hmm that's really interesting. I just figured all diesel oil turned black ASAP.

 

[yARIC008]

Originally posted by F350camper
Hmm that's really interesting. I just figured all diesel oil turned black ASAP.

yeah, i pretty much figured that too, but i can probably go take a picture for ya if ya want. The oil on the end of the dipstick looks like it just came out of the bottle.

 

[argve]

When The Enterprise got her 3rd engine (last one I installed) it took quite a while before the oil would start to turn black. Heck before the turbo you would almost think it was gasser oil at 2k miles - yes that clean looking, but after the turbo - turned black instantly. Now even with the bypass oil system she would still be black after a day of running but if you smeared the oil on your fingers you could still see that it was clean, but the blackness was there full force.

Now with my goat it takes about a 1k miles and then she makes the turn fully, has the normal traces from the old oil up until then but still fairly clean looking on the dipstick.

 

[Agnem]

The black stuff is soot, and if you've ever gotten soot on something porous, you know it's a devil of a think to try and get off. I believe it sticks to the insides of the motor, in the casting crevases and stuff. The soot probably comes from the blow by, and since the oil is spraying the bottom of the piston, the oil catches the soot right at the source, and distributes it around the engines innards. By the time our engines get their oil changed, there is so much soot stuck to the insides, there is no way to really get it cleaned, and then it leeches into the fresh oil change as soon as it starts to circulate. Travis' comments about his new engine lend evidence to my theory. A new engine would have clean innards, and would take some time for the soot to accumulate.

 

[towcat]

mel-
I've torn down enough of these engines and can definitely say with semi-regular service intervals, the internals is darn near squeaky clean outside of the oil film. Diesel rated oils without a doubt does a very good job of keeping the internals gunk-free.

 

[Agnem]

OK Calvin. You've got me there. It was just a theory.

 

[argve]

You guys should have seen the inside of the first engine I tore down out of The Enterprise. You could write you name in the sludge (soot) build up on just about anywhere inside the engine - she was not taken care of by any stretch of the means, the gunk was so thick on the valve covers/head and oil pan that it was at times over 1 inch thick and I'm not kidding either. I about died when I got that engine apart. I think the previous owned just filled her full of fuel and that was it, I highly doubt she did much of anything under the hood.

 

[budtoh3zo]

I think people like that should not own a truck tell they learn how to appresiate them

 

[hheynow]

There's a product available that cleans out the inside of engines. http://www.auto-rx.com I've used it before on my '97 7.3L PSD when it had 130,000 miles on it. After reading this thread I'm going to order some more. Now I have 202,000 miles on it. There is a one time $4.00 discount coupon available to members of on line automotive forums HERE .
HERE is Oil Guard's take on soot control.

 

[F350camper]

You'll have to let us know how clean it stays after he's put 15,000 miles on or so Eric.

 

[hheynow]

Originally posted by F350camper
You'll have to let us know how clean it stays after he's put 15,000 miles on or so Eric.

I have a 1 micron Oil Guard bypass filter, I change my oil every 4,000 miles and my Blackstone oil analysis reports are great...BUT MY OIL IS STILL BLACK AS COAL TAR. I don't really know how to measure the difference in soot in solution after a cleaning with Auto-RX, but if it gives me piece of mind...I'll go for it.