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So after reading multiple threads about soot in oil, curiosity got the better of me and I went out and wiped the dipstick on a clean, white, lint free cloth. The results made me ill. Black as coal with 80% life left. Nuts to that, says I. So I cashed in one of my free oil changes at the stealer and also got the tires rotated. Got a feeling I'm going to be doing this a lot, but I can't stand the look of that nasty oil.
 

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I mean, you could drive 100 miles and check it and it will probably already be black. It’s a diesel thing. Not saying changing early isn’t a bad thing. But oil color on our trucks has no correlation to the degradation of the oil. Run it 5k miles or so on synthetic oil and change it. If you’re really worried about it, send a sample off to Blackstone Labs.
 

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The
So after reading multiple threads about soot in oil, curiosity got the better of me and I went out and wiped the dipstick on a clean, white, lint free cloth. The results made me ill. Black as coal with 80% life left. Nuts to that, says I. So I cashed in one of my free oil changes at the stealer and also got the tires rotated. Got a feeling I'm going to be doing this a lot, but I can't stand the look of that nasty oil.
“black” is soot, the particles are extremely small, some funny # like .003. It will
not hurt your engine. All Diesel engines are like this. I changed my oil last month, checked oil it was dark immediately.
Just change it according to GM maintenance in your owners manual.
 

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The soot is from EGR. With EGR turned off via delete or tuning, the oil does not turn black, at least in my truck, even after 7.5K miles of run time. It gets dark brown, looks like it came out of a gas engine.

Recycling EGR exposes the engine to harsher conditions that not recycling EGR. Engine oil makers have responded with reformulated oils to combat the negative effects of the EGR environment so they will be able to provide the required protection that current engine designs need. Nitric acid from NOx compounds that are recirculated back into the engine through the EGR require oils with a higher base number (BN) and detergency to counteract the damaging effects of these acidic contaminants.

So ya, EGR sucks. No biggie though, my approach before tuning was to change it a little early - every 5K miles. Without EGR, the T6 I run (ya, I know T6 is not Dexos2 - no warranty anyway due to tuning) easily goes 7.5K miles with lots of life left per oil analysis reports, which show the lowest wear metal levels in any 2.8 Blackstone Labs has sampled :)

I would not lose too much sleep over the oil being black, maybe do an analysis at 5K and see what they say. If wear metals look good at that interval and I am sure they will, then just carry on with changing it every 5K, and submitting oil for analysis every other change for peace of mind. Also, a grip of oil analysis reports is nice thing to have when selling the truck.

On another EGR note, I am a big believer in catch cans and run a Provent 200. The 2.8 runs a lot of EGR and passes quite a bit of PCV oil mist. EGR + Oil mist = Goo. Lots of intake clogging goo. Remove the oil mist form the equation and you are left with dry EGR carbon that coats the intake but does not block it, which is much better than sticky accumulating goo.
 

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Bypass filtration is also an option. The filters used in a bypass system filter much smaller particles than a standard oil filter. However, high quality filters typically do a "good enough" job, and by the time soot loading is high enough to be a concern, the TBN/additive package has decreased to the point where you want new oil anyway. Check out my shitty blog... I have several UOAs posted where Blackstone has commented on the soot content: https://www.midmichiganoil.com/
 

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I think next time I'll pull a sample for testing. If for no other reason than peace of mind.
Would you please post results, with some context on how you use your vehicle? FYI, what Burgess159 said. But this is my 3rd personal diesel, and I've been checking diesel dipsticks for 45 years, and my oil gets dirty looking a lot slower than any I've seen before....
 

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I will.It will give me something to do.
 

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For your info, here is my last Blackstone Labs report, ran T6 for 7,500 miles. The wear metals and TBN numbers look fantastic.
 

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They do a great job, will be sending a sample their way next time around.
 

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So after reading multiple threads about soot in oil, curiosity got the better of me and I went out and wiped the dipstick on a clean, white, lint free cloth. The results made me ill. Black as coal with 80% life left. Nuts to that, says I. So I cashed in one of my free oil changes at the stealer and also got the tires rotated. Got a feeling I'm going to be doing this a lot, but I can't stand the look of that nasty oil.
The black is carbon, and according to an instructor at a diesel class I took in the 70's, it is an excellent lubricant. To prove the point, he put new, clean oil in a bearing tester, then dirty oil we watched him take from a big rig. The new oil seized up before the old, black oil. As long as it doesn't break down or get sludgy, "black is beautiful" in your engine. BTW back then, as a poor gear jammer, fuel was in the 60 cent a gallon range, unleaded was called white gas and only went in your camp stove, and there wasn't any ethynol in gas to ruin the carbs in my small air cooled engines.
 
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